Amendment to Annual Report Form 10 K/A

Except as described above, this Amendment does not reflect events occurring after the date of the filing of the Original Form 10-K or modify or update any of the other disclosures contained therein in any way. Accordingly, this Amendment should be read in conjunction with the Original Form 10-K and the Company's other filings with the SEC. This Amendment does not reflect events that may have occurred subsequent to the filing of the Original Form 10-K. The filing of this Amendment is not an admission that the Original Form 10-K, when filed, included any untrue statement of a material fact or omitted to state a material fact necessary to make a statement not misleading.

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1. Organization and Basis of Presentation

Revelation Biosciences, Inc. (collectively with its wholly-owned subsidiaries, the "Company" or "Revelation"), formerly known as Petra Acquisition, Inc. ("Petra"), was incorporated in Delaware on November 20, 2019. The Company was formed for the purpose of entering into a merger, share exchange, asset acquisition, stock purchase, recapitalization, reorganization or similar business combination with one or more businesses or entities. On August 29, 2021 Petra and Old Revelation signed an agreement and plan of merger (the "Business Combination Agreement"). On January 10, 2022 (the "Closing Date") the Company consummated its business combination, with Revelation Biosciences Sub, Inc. ("Old Revelation" or "Revelation Sub"), the Company's wholly owned subsidiary (the "Business Combination"). Since the Business Combination, the Company is a clinical-stage biopharmaceutical company and has been focused on the development and commercialization of immunologic therapeutics and diagnostics.

Business Combination

The Business Combination was accounted for as a reverse recapitalization with Revelation Sub as the accounting acquirer and Petra as the acquired company for accounting purposes. Accordingly, all historical financial information presented in the consolidated financial statements represents the accounts of Revelation Sub as if Revelation Sub is the predecessor to the Company. The common stock and net loss per share, prior to the Merger, have been retroactively restated as common stock and net loss per share reflecting the exchange ratio established in the Business Combination (the "Common Stock Exchange Ratio").

Petra's Common Stock, Public Warrants and Units were historically listed on the Nasdaq Capital Market under the symbols "PAIC," "PAICW" and "PAICU," respectively. On January 10, 2022, the Company's units, common stock and warrants were listed on the Nasdaq Capital Market under the symbols "REVBU", "REVB" and "REVBW", respectively.

Unit Separation

On January 13, 2023, the Company's units were mandatorily separated into one share of common stock and one Public Warrant and ceased trading on the Nasdaq Capital Market (see Note 9).

Reverse Stock Splits

On January 22, 2024, the Company filed a Certificate of Amendment of the Third Amended and Restated Certificate of Incorporation effecting a reverse stock split on January 25, 2024 with a ratio of 1-for-30(the "2024 Reverse Split"). As a result of the 2024 Reverse Split, every 30shares of the Company's issued and outstanding common stock automatically converted into oneshare of common stock, without any change in the par value per share. No fractional shares were outstanding following the 2024 Reverse Split. Any holder who would have received a fractional share of common stock automatically received an additional fraction of a share of common stock to round up to the next whole share. In addition, effective as of the same time as the 2024 Reverse Split, proportionate adjustments were made to all then-outstanding equity awards and warrants with respect to the number of shares of common stock subject to such award or warrant and the exercise price thereof. Furthermore, the number of shares of common stock available for issuance under the Company's equity incentive plans were proportionately adjusted for the 2024 Reverse Split ratio, such that fewer shares are subject to such plans. All share numbers included herein have been retroactively adjusted to reflect the 1-for-30Reverse Split (see Note 10).

On January 30, 2023, the Company filed a Certificate of Amendment of the Third Amended and Restated Certificate of Incorporation reflecting the change in authorized shares of common stock from 100,000,000to 500,000,000and effecting a reverse stock split on February 1, 2023 with a ratio of 1-for-35(the "2023 Reverse Split"). As a result of the 2023 Reverse Split, every 35shares of the Company's issued and outstanding common stock automatically converted into oneshare of common stock, without any change in the par value per share. No fractional shares were outstanding following the 2023 Reverse Split. Any holder who would have received a fractional share of common stock automatically received an additional fraction of a share of common stock to round up to the next whole share. In addition, effective as of the same time as the 2023 Reverse Split, proportionate adjustments were made to all then-outstanding equity awards and warrants with respect to the number of shares of common stock subject to such award or warrant and the exercise price thereof. Furthermore, the number of shares of common stock available for issuance under the Company's equity incentive plans were proportionately adjusted for the 2023 Reverse Split ratio, such that fewer shares are subject to such plans. All share numbers included herein have been retroactively adjusted to reflect the 1-for-35Reverse Split (see Note 10).

NASDAQ Compliance

As previously reported in 2022, the Nasdaq Stock Market ("Nasdaq") issued delist letters based on the Company's non-compliance with the bid price and stockholders' equity requirements for continued listing on the Nasdaq Capital Market, as set forth in Nasdaq Listing Rules 5550(a)(2) and 5550(b)(1), respectively. The Company's compliance plan was approved by a Nasdaq hearing panel giving the Company until April 18, 2023 to regain compliance. On February 16, 2023, the Company received formal notice from Nasdaq stating that the Company's common stock will continue to be listed and traded on Nasdaq, due to the Company having regained compliance with the minimum bid price requirement and minimum stockholders' equity requirement for continued listing on Nasdaq, and all applicable listing standards.

As previously reported on August 8, 2023, the Company received a letter from Nasdaq notifying the Company of its noncompliance with Nasdaq Listing Rule 5550(a)(2) by failing to maintain a minimum bid price for its common stock of at least $1.00per share for 30consecutive business days. The Company had until February 5, 2024, to regain compliance by having a minimum closing bid price of at least $1.00per share for at least 10consecutive business days. On February 8, 2024 the Company received a formal notice from Nasdaq stating that the Company's common stock will continue to be listed and traded on Nasdaq, due to the Company having regained compliance with the minimum bid price requirement, and all applicable listing standards.

Liquidity and Capital Resources

Going Concern

The Company has incurred recurring losses since its inception, including a net loss of $0.1million for the year ended December 31, 2023. As of December 31, 2023, the Company had an accumulated deficit of $25.5million, a stockholders' equity of $6.6million and available cash and cash equivalents of $12.0million. The Company expects to continue to incur significant operating and net losses, as well as negative cash flows from operations, for the foreseeable future as it continues to complete all necessary product development or future commercialization efforts. The Company has never generated revenue and does not expect to generate revenue from product sales unless and until it successfully completes development and obtains regulatory approval for GEM-SSI, GEM-AKI, GEM-CKD or other product candidates, which the Company expects will not be for at least several years, if ever. Additionally, taking into consideration the net proceeds of approximately $5.4million received in connection with the public offering completed in February of 2024, the Company does not anticipate that its current cash and cash equivalents balance will be sufficient to sustain operations within one-year after the date that the Company's audited financial statements for December 31, 2023 were issued, which raises substantial doubt about its ability to continue as a going concern.

To continue as a going concern, the Company will need, among other things, to raise additional capital resources. The Company plans to seek additional funding through public or private equity or debt financings. The Company may not be able to obtain financing on acceptable terms, or at all. The terms of any financing may adversely affect the holdings or the rights of the Company's stockholders. If the Company is unable to obtain funding, it could be required to delay, reduce or eliminate research and development programs, product portfolio expansion or future commercialization efforts, which could adversely affect the Company's business operations.

The audited consolidated financial statements for December 31, 2023, have been prepared on the basis that the Company will continue as a going concern, and does not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability for the Company to continue as a going concern.

Basis of Presentation

The accompanying financial statements are prepared in accordance with U.S. generally accepted accounting principles ("GAAP"). All inter-company transactions and balances have been eliminated in consolidation.

2. Summary of Significant Accounting Policies

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Prepaid Expenses and Other Current Assets

Property and Equipment, Net

Depreciation expense was $25,049for the year ended December 31, 2023 and $25,048for the year ended December 31, 2022.

Accrued Expenses

Included in accrued other expenses as of December 31, 2022, was the $5,000redemption price of the Series A Preferred Stock that automatically redeemed on January 30, 2023 upon the effectiveness of the Certificate of Amendment implementing the reverse stock split and an increase in the authorized shares of common stock of the Company (see Note 8).

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4. Commitments and Contingencies

Lease Commitments

In February 2021, Revelation Sub entered into an agreement to lease 2,140square feet of laboratory space located at 11011 Torreyana Road, Suite 102, San Diego, California (the "Lease"). In January 2023, the Company signed an amendment extending the Lease until December 31, 2023 (the "2023 Amended Lease"), with a base monthly rent equal to $9,630. The Company is required to maintain a security deposit of $5,564. The Lease contains customary default provisions, representations, warranties and covenants. In addition to rent, the Lease requires the Company to pay certain taxes, insurance and operating costs relating to the leased premises. The Company has applied the short-term lease exception as the amendment is less than twelve months. The Lease is classified as an operating lease.

Rent expense was $111,661for the year ended December 31, 2023 and $66,645for the year ended December 31, 2022, respectively.

There are nofuture minimum lease payments under the 2023 Amended Lease of the operating lease as of December 31, 2023.

Effective on January 1, 2024, Revelation Sub signed the 2024 Amended Lease (see Note 14).

Convertible Note Financing

On January 4, 2022, Revelation Sub entered into a convertible note with AXA Prime Impact Master Fund I SCA SICAV-RAIF ("AXA") for $2.5million with a fixed 10% annual interest rate, the proceeds of which were to be used by Revelation Sub to purchase shares of Petra common stock from redeeming Petra stockholders who redeemed shares of Petra common stock in connection with the Business Combination (the "Convertible Note").

On January 6, 2022, Old Revelation purchased 201shares of Petra common stock with the proceeds from the Convertible Note. Repayment of the Convertible Note was made on January 6, 2022 in accordance with the exchange terms of the Convertible Note by which 201shares of Petra common stock that had been purchased by Revelation Sub were transferred to AXA.

Total interest incurred under the Convertible Note was $14,383during the year ended December 31, 2022.

Commitments

The Company enters into contracts in the normal course of business with third party service providers and vendors. These contracts generally provide for termination on notice and, therefore, are cancellable contracts and not considered contractual obligations and commitments.

Contingencies

From time to time, the Company may become subject to claims and litigation arising in the ordinary course of business. The Company is not a party to any material legal proceedings, nor is it aware of any material pending or threatened litigation other than described below.

Legal Proceedings

On February 18, 2022, LifeSci Capital LLC filed an action against the Company in the U.S. District Court for the Southern District of New York seeking damages in the amount of approximately $5.3million plus interest for unpaid banking and advisory fees. These fees arise under contracts which were entered into prior to the Business Combination and the Company has asserted that LifeSci Capital LLC is not entitled to the fee because it violated its responsibilities by misrepresenting to Petra the funds that would be available following the Business Combination, absent which Petra would not have entered into the Business Combination Agreement. This action remains pending as of the date of this report. $1.5million of the claim relates to deferred underwriting commissions from the Petra initial public offering, which are recorded as a current liability in the financial statements as of December 31, 2023 under deferred underwriting commissions. On December 1, 2023 a Magistrate Judge issued a report recommending summary judgment in favor of LifeSci Capital LLC. On December 15, 2023, the Company filed objections to the Magistrate's report asserting that the Magistrate Judge made factual determinations not appropriate for summary judgment and misapplied the law. The Magistrate's report is a recommendation to the trial judge who is responsible for reviewing the case de novo. Other than the deferred underwriting commissions, no liabilities are reflected in the financial statements as the amount of any additional liability cannot be determined at this time.

On September 27, 2022, A-IR Clinical Research Ltd. ("A-IR") filed a claim against the Company in the High Court of Justice, in the Business and Property Courts of England and Wales, seeking £1.6million in unpaid invoices, plus interest and costs, relating to the Company's viral challenge study. The Company is disputing the claim because many of the invoices relate to work that was not performed and A-IR had misrepresented its qualifications to perform the contracted work. Since this proceeding is at a very early stage, no liability is reflected in the financial statements as the amount of any liability cannot be determined at this time.

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5. PIPE Investment

On January 25, 2022, the Company closed a private placement of 1,232shares of unregistered common stock, 1,232unregistered pre-funded warrants to purchase common stock with an exercise price of $0.01050, which did not have an expiration (the "Class A Pre-Funded Warrants"), and 2,464unregistered warrants to purchase common stock with an exercise price of $3,454.50per share of common stock which expire on July 25, 2027(the "Class A Common Stock Warrants") at a combined purchase price of $3,150.00per share of common stock or $3,149.98950per Class A Pre-Funded Warrant and associated Class A Common Stock Warrants to an institutional investor (the "PIPE Investment"). Net proceeds to the Company were $7.3million.

Roth Capital Partners, LLC ("Roth") was engaged by the Company to act as its exclusive placement agent for the private placement. The Company paid Roth a cash fee equal to 6.0% of the gross proceeds received by the Company in the private placement, totaling $465,600and issued warrants to purchase up to 345shares of common stock with an exercise price of $3,454.50which expire on July 25, 2027(the "Class A Placement Agent Common Stock Warrants"). The Class A Placement Agent Common Stock Warrants have substantially the same terms as the Class A Common Stock Warrants.

In connection with the private placement, the Company entered into a registration rights agreement with the institutional investor, pursuant to which the Company agreed to file a registration statement to register for resale of the shares of common stock, shares of common stock underlying the Class A Pre-Funded Warrants and shares of common stock underlying the Class A Common Stock Warrants. The company filed the registration statement with the SEC on Form S-1 (File No. 333-262410) on January 28, 2022 and it became effective on February 7, 2022.

On February 22, 2022, the Company received a notice of cash exercise for the total outstanding Class A Pre-Funded Warrants issued in connection with the PIPE Investment for 1,232shares of common stock at a purchase price of $12.94. As of December 31, 2023 and December 31, 2022, there were no Class A Pre-Funded Warrants outstanding.

Using the Black-Scholes option pricing model, the Class A Common Stock Warrants were valued in the aggregate at $3.6million and the Class A Placement Agent Common Stock Warrants were valued in the aggregate at $0.5million. Both were included in the issuance costs of the private placement and treated as equity (see Note 12).

6. 2022 Public Offering

On July 28, 2022, the Company closed a public offering of 7,937shares of its common stock and 8,333,334warrants to purchase up to 7,937shares of its common stock with an exercise price of $630.00per share which expire on July 28, 2027(the "Class B Common Stock Warrants") at a combined offering price of $630.00per share and associated warrant (the "July 2022 Public Offering"). Net proceeds to the Company from the offering were $4.5million.

Roth was engaged by the Company to act as its exclusive placement agent for the July 2022 Public Offering. The Company paid Roth a cash fee equal to 7.0% of the gross proceeds received by the Company in the public offering, totaling $350,000and issued warrants to purchase up to 556shares of common stock with an exercise price of $787.50per share which expire on July 25, 2027(the "Class B Placement Agent Common Stock Warrants").

The shares of common stock, the shares of common stock underlying the Class B Common Stock Warrants and the shares of common stock underlying the Class B Placement Agent Common Stock Warrants were registered with the SEC on Form S-1 (File No. 333-266108) and was declared effective by the SEC on July 25, 2022.

Using the Black-Scholes option pricing model, the Class B Common Stock Warrants were valued in the aggregate at $4.5million and the Class B Placement Agent Common Stock Warrants were valued in the aggregate at $0.3million. Both were included in the issuance costs of the July 2022 Public Offering and treated as equity (see Note 12).

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7. 2023 Public Offering

On February 13, 2023, the Company closed a public offering of 96,287shares of its common stock, 11,214pre-funded warrants to purchase shares of common stock with an exercise price of $0.003which did not have an expiration date (the "Class C Pre-Funded Warrants") and 6,450,000warrants to purchase up to 215,000shares of common stock with an exercise price of $160.80which expire on February 14, 2028(the "Class C Common Stock Warrants") at a combined offering price of $144.90per share of common stock and two Class C Common Stock Warrants, or $144.8970per Class C Pre-Funded Warrant and two Class C Common Stock Warrants (the "February 2023 Public Offering"). Net cash proceeds to the Company from the offering were $14.0million.

Roth was engaged by the Company to act as its exclusive placement agent for the February 2023 Public Offering. The Company paid Roth a cash fee equal to 8.0% of the gross proceeds received by the Company in the public offering, totaling $1.2million.

The shares of common stock, the shares of common stock underlying the Class C Pre-Funded Warrants and the shares of common stock underlying the Class C Common Stock Warrants were registered with the SEC on Form S-1 (File No. 333-268576) and was declared effective by the SEC on February 9, 2023.

Between February 14, 2023 and April 6, 2023, the Company received notices of cash exercise for the Class C Pre-Funded Warrants issued in connection with the February 2023 Public Offering for 11,214shares of common stock at a total purchase price of $33.64. As of December 31, 2023, there were noClass C Pre-Funded Warrants outstanding.

Using a Monte-Carlo simulation model, the Class C Common Stock Warrants were valued in the aggregate at $14.0million and included in the issuance costs of the February 2023 Public Offering and treated as a liability (see Note 12).

From March 13, 2023 to December 31, 2023, the Company issued 79,521shares of common stock in connection with notices of alternative cashless exercise for the Class C Common Stock Warrants issued in connection with the February 2023 Public Offering. As of December 31, 2023, there were 487,160of Class C Common Stock Warrants outstanding to purchase up to 16,239shares of common stock.

8. Preferred Stock

Revelation Authorized Preferred Stock

The Certificate of Amendment of the Company authorizes up to 5,000,000shares of preferred stock, $0.001par value per share, which may be issued as designated by the Board of Directors without stockholder approval. As of December 31, 2023 and as of the date of this Report, there were no shares of preferred stock issued and outstanding.

Series A Preferred Stock

On December 19, 2022, the Company closed the sale of one share of the Company's Series A Preferred Stock, par value $0.001per share, to its Chief Executive Officer for $5,000.00. The outstanding share of Series A Preferred Stock was automatically redeemed for $5,000.00on January 30, 2023 upon the effectiveness of the Certificate of Amendment implementing the reverse stock split and the increase in authorized shares of common stock of the Company.

The Series A Preferred Stock had 50,000,000votes and voted together with the outstanding shares of the Company's common stock as a single class exclusively with respect to any proposal to amend the Company's Restated Certificate of Incorporation to effect a reverse stock split of the Company's common stock and to increase the number of authorized shares of common stock of the Company. The Series A Preferred Stock voted, without action by the holder, on any such proposal in the same proportion as shares of common stock voted. The Series A Preferred Stock otherwise had no voting rights except as otherwise required by the General Corporation Law of the State of Delaware.

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9. Units

In connection with Petra's IPO, in October of 2020, Petra issued unit's that consisted of one share of common stock and one warrant exercisable for 1/1,050 of a share of common stock with an exercise price of $12,075.00per share which expire on January 10, 2027 (the "Public Warrants"), which traded on the Nasdaq Capital Market under the ticker symbol REVBU.

As disclosed in Note 1, on January 13, 2023, the Company's units were mandatorily separated, ceased to exist and stopped trading on the Nasdaq Capital Market. At the time of separation there were 1,688,598units separated, which represented 1,609shares of common stock and 1,688,598Public Warrants. Nonew shares of common stock or Public Warrants were issued in connection with the separation.

10. Common Stock

The Company is authorized under its articles of incorporation, as amended, to issue 500,000,000shares of common stock, par value $0.001per share.

Common Stock Issuance due to the Business Combination

On the Closing Date, the Company issued an aggregate of 64,021shares of common stock in exchange for all outstanding Revelation Sub stock. Net proceeds from the Business Combination were $11.9million, of which $7.7million was escrowed pursuant to a forward share purchase agreement entered into by Petra and an institutional investor and $4.2million was released to Revelation.

Common Stock Issuance during the year ended December 31, 2022

On January 23, 2022, the Company issued 1,232shares of common stock in connection with the PIPE Investment. The Company received net proceeds of $7.3million.

On January 31, 2022, the Company issued 286shares of common stock as collateral to Loeb & Loeb, LLP as part of a payment deferral of legal fees in connection with the Business Combination.

On February 2, 2022, the Company issued 2shares of common stock in connection with a notice of cash exercise for the Company's Rollover Warrants with a total purchase price of $5,073.

On February 4, 2022, the Company cancelled 715shares in connection with the exercise of the forward share purchase agreement and approximately $7.7million that was in escrow was paid to an institutional investor.

On February 22, 2022, the Company issued 1,232shares of common stock in connection with a notice of cash exercise for the Class A Pre-Funded Warrants issued in connection with the PIPE Investment with a total purchase price of $12.94.

On July 28, 2022, the Company issued 7,937shares of its common stock in connection with the July 2022 Public Offering. The Company received net proceeds of $4.5million.

On July 29, 2022, the Company issued 106shares of common stock in connection with vested Rollover RSU awards.

Common Stock Issuance during the year ended December 31, 2023

On February 13, 2023, the Company issued 96,287shares of its common stock in connection with the February 2023 Public Offering. The Company received net cash proceeds of $14.0million.

On February 14, 2023, the Company issued 1,100shares of common stock in connection with a notice of cash exercise for Class C Pre-Funded Warrants issued in connection with the February 2023 Public Offering with a total purchase price of $3.30.

On March 2, 2023, the Company issued 5,334shares of common stock in connection with a notice of cash exercise for the Class C Pre-Funded Warrants issued in connection with the February 2023 Public Offering with a total purchase price of $16.00.

From March 13, 2023 to March 31, 2023, the Company issued 32,190shares of common stock in connection with notices of alternative cashless exercise for the Class C Common Stock Warrants issued in connection with the February 2023 Public Offering.

From April 1, 2023 to June 30, 2023, the Company issued 47,331 shares of common stock in connection with notices of alternative cashless exercise for the Class C Common Stock Warrants issued in connection with the February 2023 Public Offering.

On April 6, 2023, the Company received a notice of cash exercise for the Class C Pre-Funded Warrants issued in connection with the February 2023 Public Offering for 4,780shares of common stock at purchase price of $14.34.

On April 18, 2023, the Company issued 140shares of common stock in connection with vested Rollover RSU awards.

As of December 31, 2023 and December 31, 2022, 264,537and 77,375shares of common stock were issued and outstanding, respectively. As of December 31, 2023, nocash dividends have been declared or paid.

11. Stock-Based Compensation

2021 Equity Incentive Plan

In January 2022, in connection with the Business Combination, the Board of Directors and the Company's stockholders adopted the 2021 Equity Incentive Plan (the "2021 Plan") and reserved 1,232authorized shares of common stock for issuance under the plan. The 2021 Plan is administered by the Board of Directors. Vesting periods and other restrictions for grants under the 2021 Plan are determined at the discretion of the Board of Directors. Grants to employees, officers, directors, advisors, and consultants of the Company typically vest over oneto four years. In addition, the number of shares of stock available for issuance under the 2021 Plan will be automatically increased each January 1, and began on January 1, 2022, by 10% of the aggregate number of outstanding shares of our common stock from the first day of the preceding calendar year to the first day of the current calendar year or such lesser number as determined by our board of directors. On July 14, 2023 at the Company's 2023 Annual Meeting of Stockholders, an amendment to the 2021 Equity Incentive Plan to increase the number of shares reserved under the Plan to 21,623was approved.

Under the 2021 Plan, stock options and stock appreciation rights are granted at exercise prices determined by the Board of Directors which cannot be less than 100% of the estimated fair market value of the common stock on the grant date. Incentive stock options granted to any stockholders holding 10% or more of the Company's equity cannot be granted with an exercise price of less than 110% of the estimated fair market value of the common stock on the grant date and such options are not exercisable after five yearsfrom the grant date.

As of December 31, 2023, there were 20,466shares available for future grants under the 2021 Plan.

Restricted Stock Units

At the Closing Date of the Business Combination, all Revelation Sub RSU award holders received a Rollover RSU award in exchange for each RSU award of Revelation Sub that vest in accordance with the original terms of the award. The Company determined this to be a Type I modification but did not record any incremental stock-based compensation expense since the fair value of the modified awards immediately after the modification was not greater than the fair value of the original awards immediately before the modification.

The Rollover RSU awards have time-based and milestone-based vesting conditions. Under time-based vesting conditions, the Rollover RSU awards vest quarterly over one-yearfor grants to the Board of Directorsand quarterly over four yearsor 25% on the one-year anniversary and the remainder vesting monthly thereafter for grants to officers, employees and consultants.The milestone-based vesting conditions vested on the Closing Date of the Business Combination.

As of December 31, 2023 and December 31, 2022, the Company has a total of 94and 234Rollover RSU awards for shares of common stock outstanding, respectively. As of December 31, 2023, 51Rollover RSU awards have fully vested but are unissued and no Rollover RSU awards have been forfeited. As of December 31, 2023, 94Rollover RSU awards will vest and be issued over the next 1.1years. Each Rollover RSU award converts to one share of common stock.

Stock Options

The Company has granted stock options which(i) vest fully on the date of grant; (ii) vest 25% on the one-year anniversary of the grant date or the employees hiring date, with the remainder vesting quarterly thereafter; or (iii) vest quarterly over one-year, for grants to Board of Directors, officers and employees.Stock options have a maximum term of 3or 10 years.

For the year ended December 31, 2023, the weighted-average Black-Scholes value per stock option was $314.03.The fair value of the stock options was estimated using the Black-Scholes option pricing model with the following weighted-average assumptions:

Expected volatility is based on the historical volatility of shares of the Company's common stock. In determining the expected term of stock options, the Company uses the "simplified" method. Under this method, the expected term is presumed to be the midpoint between the average vesting date and the end of the contractual term. The risk-free interest rate is based on the U.S. Treasury yield for a period consistent with the expected term of the stock options in effect at the time of the grants. The dividend yield assumption is based on the expectation of no future dividend payments by the Company. In addition to assumptions used in the Black-Scholes model, the Company reduces stock-based compensation expense based on actual forfeitures in the period that each forfeiture occurs.

Stock-Based Compensation Expense

As of December 31, 2023, there was $106,903and $67,377of unrecognized stock-based compensation expense related to Rollover RSU awards and stock options, respectively. The unrecognized stock-based compensation expense is expected to be recognized over a period of 1.1years and 2.2years for Rollover RSU's and stock options, respectively.

12. Warrants

Public Warrants

In connection with Petra's IPO, Petra issued and has outstanding 10,511,597Public Warrants to purchase an aggregate of 10,012shares of common stock with an exercise price of $12,075.00per share which expire on January 10, 2027. The Public Warrants trade on the Nasdaq Capital Market under the ticker symbol REVBW.

The Company may redeem the Public Warrants at a price of $0.01per Public Warrant upon not less than 30 days' prior written notice of redemption if, and only if, the reported last sale price of the Company's common stock equals or exceeds $18,900.00per share for any 20 trading days within a 30-trading day period ending on the third business day prior to the notice of redemption to the Public Warrant holders; and if, and only if, there is a current registration statement in effect with respect to the shares of common stock underlying the Public Warrants. If the Company calls the Public Warrants for redemption, management will have the option to require all holders that wish to exercise the Public Warrants to do so on a "cashless basis," as described in the warrant agreement.

Rollover Warrants

Prior to the Merger, Revelation Sub issued warrants to a placement agent to purchase up to 157shares of common stock with an exercise price of $2,816.92per share which expire on January 31, 2027, valued on the issuance date in the aggregate at $326,675. At the Closing Date of the Business Combination, all warrant holders received a Rollover Warrant, which was exercisable in accordance with its original issuance.

On February 2, 2022, the Company received a notice of cash exercise for the Company's Rollover Warrants for 2shares of common stock at a purchase price of $5,073. As of December 30, 2023, there were 155Rollover Warrants remaining to be exercised or exchanged.

Class A Pre-Funded Warrants

In connection with the PIPE Investment, the Company issued pre-funded warrants to an institutional investor to purchase up to 1,232shares of common stock at an exercise price of $0.0105per share.

On February 22, 2022, the Company received a notice of cash exercise for the Class A Pre-Funded Warrants issued in connection with the PIPE Investment for 1,232shares of common stock at purchase price of $12.94. As of December 31, 2023, there were no Class A Pre-Funded Warrants outstanding.

Class A Common Stock Warrants

In connection with the PIPE Investment, the Company issued warrants to an institutional investor to purchase up to 2,464shares of common stock at an exercise price of $3,454.50per share, valued on the PIPE Investment purchase date in the aggregate at $3.6million and included in the issuance costs of the PIPE Investment. The warrants were exercisable immediately upon issuance, provide for a cash or cashless exercise right and expire on July 25, 2027.

Class A Placement Agent Common Stock Warrants

In connection with the PIPE Investment, the Company issued warrants to Roth to purchase an aggregate of 345shares of common stock at an exercise price of $3,454.50per share, valued on the PIPE Investment purchase date in the aggregate at $0.5million and included in the issuance costs of the PIPE Investment. The warrants were exercisable immediately upon issuance, provide for a cash or cashless exercise right and expire on July 25, 2027.

Class B Common Stock Warrants

In connection with the July 2022 Public Offering, the Company issued and has outstanding 8,333,334warrants to purchase an aggregate of 7,937shares of common stock at an exercise price of $630.00per share, valued on the public offering purchase date in the aggregate at $4.5million and included in the issuance costs of the public offering. The warrants were exercisable immediately upon issuance, provide for a cash or cashless exercise right and expire on July 28, 2027.

Class B Placement Agent Common Stock Warrants

In connection with the July 2022 Public Offering, the Company issued warrants to the Placement Agent to purchase up to 556shares of common stock at an exercise price of $787.50per share, valued on the public offering purchase date in the aggregate at $0.3million and included in the issuance costs of the public offering. The warrants were exercisable immediately upon issuance, provide for a cash or cashless exercise right and expire on July 25, 2027.

Class C Pre-Funded Warrants

In connection with the February 2023 Public Offering, the Company issued pre-funded warrants to purchase up to 11,214shares of common stock at an exercise price of $0.003per share. Between February 14, 2023 and April 6, 2023, the Company received notices of cash exercise for the Class C Pre-Funded Warrants issued in connection with the February 2023 Public Offering for 336,400shares of common stock at a total purchase price of $33.64. As of December 31, 2023, there were noClass C Pre-Funded Warrants outstanding.

Class C Common Stock Warrants

In connection with the February 2023 Public Offering, the Company issued 6,450,000warrants to purchase up to 215,000shares of common stock at anexercise price of $160.80per share, valued on the public offering purchase date in the aggregate at $13,996,500and included in the issuance costs of the public offering. The warrants were exercisable immediately upon issuance, provide for a cash, cashless exercise right or an alternative cashless exercise right for 0.4shares of common stock per Class C Common Stock Warrant and expire on February 14, 2028.

The Company accounted for the Class C Common Stock Warrants as current liabilities based upon the guidance of ASC 480 and ASC 815. The Company evaluated the Class C Common Stock Warrants under ASC 815-40, Derivatives and Hedging-Contracts in Entity's Own Equity ("ASC 815-40") and concluded that they do not meet the criteria to be classified in stockholders' equity.

The Company concluded that the multiplier of 0.4shares of common stock per Class C Common Stock Warrant used in the alternative cashless exercise precludes the Class C Common Stock Warrants from being considered indexed to the Company's stock. The Company recorded the Class C Common Stock Warrants as current liabilities on the balance sheet at fair value, with subsequent changes in their respective fair values recognized in the consolidated statements of operations at each reporting date. Estimating fair values of liability-classified financial instruments requires the development of estimates that may, and are likely to, change over the duration of the instrument with related changes in internal and external market factors. In addition, option-based techniques are highly volatile and sensitive to changes in the trading market price of the Company's common stock. Because liability-classified financial instruments are initially and subsequently carried at fair value, the Company's financial results will reflect the volatility in these estimate and assumption changes. Changes in fair value are recognized as a component of other income (expense) in the consolidated statements of operations.

At the date of issuance, the Company valued the Class C Common Stock Warrants using a Monte-Carlo simulation model with a fair value of $14.0million.

As of December 31, 2023, the Company received notices of alternative cashless exercises for 5,962,840Class C Common Stock Warrants issued in connection with the February 2023 Public Offering for 79,521shares of common stock.

As of December 31, 2023, the Company re-valued 487,160 outstanding Class C Common Stock Warrants to purchase up to 16,239shares of common stock using a Monte-Carlo simulation model with a fair value of $0.1million. For the year ended December 31, 2023, the gain of $8.3million, respectively, resulting from the change in the fair value of the liability for the unexercised warrants was recorded as a change in fair value of the warrant liability in the accompanying consolidated statements of operations for the year ended December 31, 2023.

13. Income Taxes

The Company did not record a provision for income taxes for the years ended December 31, 2023 and December 31, 2022 due to a full valuation allowance against its deferred tax assets.

As of December 31, 2023 and 2022, a full valuation allowance of $10,503,924and $8,499,983, respectively, was established against its deferred tax assets due to the uncertainty surrounding the realization of such assets. The valuation allowance increased by$2,003,941and $4,012,802in 2023 and 2022, respectively, due to the increase in the deferred tax assets by the same amount; primarily due to net operating loss carryforwards and the mandatory capitalization of qualified research and development expenses in 2023.

As of December 31, 2023, the Company had federal and state net operating loss carryforwards of $23,777,049and $33,468,573, respectively. As of December 31, 2022, the Company had federal and state net operating loss carryforwards of $18,224,037and $24,505,008, respectively. Federal net operating losses carryforward indefinitely. State net operating loss carryforwards will begin to expire in 2026.

The Company had estimated federal research and development credit carryforwards of $93,915as of December 31, 2023 and 2022. The federal research tax credit carryforwards will begin to expire in 2040. The Company had estimated state research and development credit carryforwards of $349,658and $292,083as of December 31, 2023 and 2022, respectively. The California state credits carryforward indefinitely.

Pursuant to Section 382 and 383 of the Internal Revenue Code ("IRC"), utilization of the Company's federal net operating loss carryforwards and research and development credit carryforwards may be subject to annual limitations in the event of any significant future changes in its ownership structure. These annual limitations may result in the expiration of net operating loss and research and development credit carryforwards prior to utilization. The Company has not completed an IRC Section 382 and 383 analyses regarding the limitation of net operating loss and research and development credit carryforwards.

No liability is recorded on the financial statements related to uncertain tax positions. There are nounrecognized tax benefits as of December 31, 2023 and 2022. The Company does not expect that uncertain tax benefits will materially change in the next 12 months.

The Company's policy is to record estimated interest and penalties related to uncertain tax benefits as income tax expense. As of December 31, 2023 and 2022, the Company had noaccrued interest or penalties recorded related to uncertain tax positions.

The Company is subject to taxation in the U.S. and various state jurisdictions. The Company's tax returns since inception are subject to examination by the U.S. and various state tax authorities. The Company is not currently undergoing a tax audit in any federal or state jurisdiction.

14. Subsequent Events

Third Amendment to Lease

In February 2024, Revelation Sub amended the 2023 Amended Lease (the "2024 Amended Lease") to expire on November 30, 2024, equal to an additional 11calendar months with a base monthly rent equal to $5,350. Effective on January 1, 2024, Revelation Sub signed the 2024 Amended Lease. The Company will pay $58,850of rent expense over the life of the 2024 Amended Lease.

Class C Common Stock Warrant Exercise

As of March 20 2023, the Company received notices for 254,800Class C Common Stock Warrants issued in connection with the February 2023 Public Offering for 3,398shares of common stock. As of March 18, 2024, there are 232,360Class C Common Stock Warrants outstanding to purchase 7,746shares of common stock.

February 2024 Public Offering

On February 5, 2024, the Company closed a public offering of (i) an aggregate of 128,470shares of its common stock, par value $0.001per share and pre-funded warrants to purchase up to an aggregate of 1,236,530shares of common stock which did not have an expiration date (the "Class D Pre-Funded Warrants") and (ii) 2,730,000warrants to purchase shares of common stock which expire February 5, 2029("Class D Common Stock Purchase Warrants") at a combined offering price of $4.53per share of common stock and two Class D Common Stock Warrants, or $4.5299per Class D Pre-Funded Warrant and two Class D Common Stock Warrants, resulting in gross proceeds of approximately $6.2million (the "February 2024 Public Offering"). As of December 31, 2023, the Company recorded $71,133of deferred offering costs. The Class D Pre-Funded Warrants do not expire and have an exercise price of $0.0001per share. The Class D Common Stock Warrants will have an exercise price of $4.53per share, are exercisable upon issuance, and will expire five yearsfollowing the date of issuance. The net proceeds to the Company from the offering were approximately $5.4million, after deducting the placement agent's fees and other offering expenses payable by the Company. The Company intends to use the net proceeds from this offering to further the development of GEM-SSI, GEM-AKI and GEM-CKD including the (i) to conduct, a combined Phase 1a clinical study for GEM-SSI and GEM-AKI, (ii) to conduct, a Phase 1b clinical study for GEM-SSI for the prevention of surgical site infection in colorectal surgery, (iii) to conduct, a Phase 1b clinical study for GEM-AKI for the prevention and treatment of AKI due to cardiac surgery, (iv) necessary preclinical work for GEM-CKD, (v) continue to develop other products and therapies, and (vi) fund working capital and general corporate purposes using any remaining amounts. A registration statement on Form S-1, and subsequently amended (File No. 333-276232) relating to these securities has been filed with the SEC and was declared effective by the SEC on January 31, 2024.

Roth Capital Partners, LLC (the "Placement Agent') was engaged by the Company to act as its exclusive placement agent for the public offering. The Company agreed to pay the Placement Agent a cash fee equal to 8.0% of the gross proceeds received by the Company in the public offering, totaling approximately $0.4million.

As part of the February 2024 Public Offering, the exercise price of the Class C Common Stock Warrants issued in the February 2023 Public Offering was reset to $4.53.

Regaining NASDAQ Compliance

As previously reported on August 8, 2023, the Company received a letter from Nasdaq notifying the Company of its noncompliance with Nasdaq Listing Rule 5550(a)(2) by failing to maintain a minimum bid price for its common stock of at least $1.00per share for 30consecutive business days. The Company had until February 5, 2024, to regain compliance by having a minimum closing bid price of at least $1.00per share for at least 10consecutive business days. On February 8, 2024 the Company received a formal notice from Nasdaq stating that the Company's common stock will continue to be listed and traded on Nasdaq, due to the Company having regained compliance with the minimum bid price requirement, and all applicable listing standards.

Class D Pre-Funded Warrant Exercises

As of March 18, 2024, the Company received notices of cash exercises for the Class D Pre-Funded Warrants issued in connection with the February 2024 Public Offering for 1,236,530shares of common stock at purchase price of $0.0001. As of March 18, 2024, there are noClass D Pre-Funded Warrants outstanding.

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