Corporate Action, Amendments to Bylaws (Form 8-K)

To the extent required by Item 3.03 of Form 8-K,the information set forth under Item 5.03 of this Current Report on Form 8-Kis incorporated by reference into this Item 3.03.

On March 26, 2026, Advantage Solutions Inc. (the "Company") effected a 1-for-25reverse stock split of its Class A common stock $0.0001 (the "Common Stock") (the "Reverse Stock Split"). As previously disclosed, at its special meeting of stockholders held on March 16, 2026 (the "Special Meeting"), the stockholders of the Company approved a proposal to authorize the Company's Board of Directors (the "Board"), in its discretion following the Special Meeting, to amend the Company's Third Amended and Restated Certificate of Incorporation (the "Certificate of Incorporation") to effect a reverse stock split of all of the outstanding shares of the Common Stock, par value $0.0001 per share, in a ratio within the range from each whole number between and including ten (10) and twenty-five (25), with a corresponding reduction in authorized shares of Common Stock and authorized but unissued shares of preferred stock, no par value. On March 16, 2026, following the Special Meeting, the Board approved the Reverse Stock Split at a ratio of 1-for-25.On March 26, 2026, the Company filed with the Secretary of State of the State of Delaware a certificate of amendment (the "Certificate of Amendment") to amend the Certificate of Incorporation to effect the Reverse Stock Split. The Reverse Stock Split has become effective at 5:00 p.m., Eastern Time, on March 26, 2026.

As a result of the Reverse Stock Split, every 25 shares of Common Stock issued or outstanding were automatically reclassified into one new share of Common Stock, subject to the treatment of fractional shares as described below, without any action on the part of the holders. Proportionate adjustments will be made to the number of shares underlying the Company's outstanding equity awards, as applicable, as well as to the number of shares issuable under the Company's equity incentive plans and certain existing agreements, as well as the exercise price, as applicable. The Common Stock issued pursuant to the Reverse Stock Split remain fully paid and non-assessable.The Reverse Stock Split did not affect the par value of the Common Stock.

No fractional shares will be issued in connection with the Reverse Stock Split. Stockholders who would otherwise be entitled to receive fractional shares as a result of the Reverse Stock Split will be entitled to a cash payment in lieu thereof at a price equal to the fraction to which the stockholder would otherwise be entitled multiplied by the closing sales price per share of the Common Stock (as adjusted to give effect to the Reverse Stock Split) on the Nasdaq Global Select Market on March 26, 2026, the last trading day immediately preceding the effective time of the Reverse Stock Split.

Trading of the Common Stock on the Nasdaq Global Select Market is expected to commence on a split-adjusted basis when the market opens on March 27, 2026, under the existing trading symbol "ADV." The new CUSIP number for the Common Stock following the Reverse Stock Split is 00791N 201.

The foregoing description of the Certificate of Amendment is qualified in its entirety by reference to the full text of the Certificate of Amendment, a copy of which is filed as Exhibit 3.1 to this Current Report on Form 8-Kand is incorporated herein by reference.