Material Event - Form 425

As previously announced, on August 26, 2024, CrossFirst Bankshares, Inc., a Kansas corporation ("CrossFirst"), and First Busey Corporation, a Nevada corporation ("Busey"), entered into an Agreement and Plan of Merger (the "Merger Agreement") pursuant to which CrossFirst will merge with and into Busey, with Busey as the surviving corporation in the merger (the "Merger"). Following the Merger, at a date and time as determined by Busey, CrossFirst Bank, a Kansas state-chartered bank and a wholly owned subsidiary of CrossFirst, will merge with and into Busey Bank, an Illinois state-chartered bank and a wholly owned subsidiary of Busey, with Busey Bank as the surviving bank. The transaction is described in more detail in CrossFirst's Current Report on Form 8-K filed with the U.S. Securities and Exchange Commission (the "SEC") on August 27, 2024.

In connection with the proposed transaction, Busey filed a registration statement on Form S-4 (the "Registration Statement") with the SEC on October 18, 2024 and Amendment No. 1 to the Registration Statement on November 8, 2024 containing a joint proxy statement/prospectus of CrossFirst and Busey (as amended, the "joint proxy statement/prospectus"). The Registration Statement was declared effective by the SEC on November 13, 2024. On November 13, 2024, the joint proxy statement/prospectus was filed by CrossFirst with the SEC as a definitive proxy statement on Schedule 14A and by Busey with the SEC as a definitive proxy statement/prospectus, and CrossFirst and Busey first mailed the joint proxy statement/prospectus to their respective stockholders on or about November 13, 2024.

Following the filing of the joint proxy statement/prospectus and as of the date of this Current Report on Form 8-K, purported stockholders of CrossFirst have filed two lawsuits against CrossFirst, the individual members of the CrossFirst board of directors, and/or Busey. The first lawsuit captioned Joel Zalvin v. CrossFirst Bankshares, Inc., et al., was filed in the District Court of Johnson County, Kansas in the 10th Judicial District on November 26, 2024 (the "Zalvin Complaint"). The second lawsuit, captioned Stephen Bushansky v. CrossFirst Bankshares, Inc., et al., was filed in the District Court of Johnson County, Kansas in the 10th Judicial District on November 29, 2024 (the "Bushansky Complaint" and together with the Zalvin Complaint, the "Complaints"). Additionally, beginning on October 24, 2024, CrossFirst and Busey have received demand letters from counsel representing other individual purported stockholders of CrossFirst and Busey (collectively, the "Demands" and, together with the Complaints, the "Matters"). The Matters allege, among other things, that the defendants caused a false and misleading registration statement relating to the Merger to be filed with the SEC in violation of Section 14(a) and Section 20(a) of the Securities Exchange Act of 1934, as amended, and Rule 14a-9 promulgated thereunder, breached their fiduciary obligations under state law, and/or committed negligence and negligent misrepresentation and concealment under state common law.

CrossFirst and Busey believe that the claims asserted in the Matters are without merit and supplemental disclosures are not required or necessary under applicable laws. However, in order to avoid the risk that the Matters delay or otherwise adversely affect the Merger, and to minimize the costs, risks and uncertainties inherent in litigation, and without admitting any liability or wrongdoing, CrossFirst and Busey are supplementing the joint proxy statement/prospectus as described in this Current Report on Form 8-K. CrossFirst, the other named defendants and Busey deny that they have violated any laws or breached any fiduciary duties. Nothing in this Current Report on Form 8-K shall be deemed an admission of the legal necessity or materiality under applicable laws of any of the disclosures set forth herein or in the joint proxy statement/prospectus. To the contrary, CrossFirst, the other named defendants and Busey specifically deny all allegations in the Matters and that any additional disclosure was or is required in the joint proxy statement/prospectus. CrossFirst or Busey may receive additional similar demand letters or may be named in similar complaints. If such complaints are filed, absent new or different allegations that are material, CrossFirst and Busey will not necessarily announce such additional filings.