Company: OSBC
Filing Date: 2025-05-06
Form Type: S-4/A
Source: 0001104659-25-045103
Chunk: 22

Company: OLD SECOND BANCORP INC
Filing Date: 2025-05-06
Form: S-4/A
Chunk 22
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 forma per share amounts of Bancorp Financial were calculated by multiplying the pro forma combined amounts by the fixed exchange ratio of 2.5814 shares of Old Second common stock for each share of Bancorp Financial common stock. (2) Pro forma combined cash dividends paid per share are based on Old Second’s historical dividends paid. NA — Not applicable. Treatment of Bancorp Financial Equity Awards (page 63) At the effective time of the merger, each outstanding restricted stock unit granted under Bancorp Financial’s equity compensation plan will fully vest and be converted into the right to receive the same merger consideration — cash and stock — as other shares of Bancorp Financial common stock. The consideration will be paid by Old Second within ten business days following the closing. Applicable tax withholdings will be deducted first from the cash portion and, if necessary, from the stock portion unless the

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holder elects otherwise. For more information, see “The Merger Agreement — Treatment of Bancorp Financial Equity Awards” on page 63.

Recommendation of the Bancorp Financial Board of Directors (page 39)

The Bancorp Financial board of directors believes that the merger agreement and the transactions contemplated by the merger agreement are in the best interests of Bancorp Financial and its stockholders. Bancorp Financial’s board of directors unanimously recommends that its stockholders vote “

#### FOR
” the proposal to adopt the merger agreement, “

#### FOR
” the stockholders agreement amendment proposal and “

#### FOR
” adjournment of the Bancorp Financial special meeting, if necessary or appropriate, to solicit additional proxies if there are insufficient votes at the time of the special meeting to adopt the merger agreement or approve the proposed amendments to the stockholders agreement. For a more detailed discussion of the Bancorp Financial board of directors’ recommendation, see the section entitled “The Merger — Recommendation of the Bancorp Financial Board of Directors and Reasons for the Merger” beginning on page 39.

### Opinion of Bancorp Financial’s Financial Advisor (page 42)
In connection with the merger, Bancorp Financial’s financial advisor, Keefe, Bruyette & Woods, Inc. (“KBW”), delivered a written opinion, dated February 18, 2025, to the Bancorp Financial board of directors as to the fairness, from a financial point of view and as of the date of the opinion, to the holders of Bancorp Financial common stock of the merger consideration (defined in KBW’s opinion as the per share cash consideration