Old Second Bancorp (OSBC) stock is back in focus after director Dennis Klaeser resigned from the boards of both the holding company and Old Second National Bank on June 5, 2026.

The boardroom change comes at a time when Old Second Bancorp’s share price has been firming, with a 30 day share price return of 4.74% and a year to date share price return of 13.35%. The 1 year total shareholder return stands at 30.28% and the 5 year total shareholder return at 88.71%, suggesting momentum has been building over both shorter and longer periods.

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So with Old Second Bancorp showing solid recent returns and trading about 5% below the current analyst price target, is the stock still undervalued, or are markets already pricing in its future growth potential?

Most Popular Narrative: 4.8% Undervalued

Old Second Bancorp's most followed valuation narrative pegs fair value at $23.20, slightly above the last close at $22.08. This frames a modest undervaluation story built on execution and credit discipline.

The recent Evergreen Bank acquisition is performing ahead of expectations, providing higher-than-expected profitability and a more favorable asset mix, which is expected to drive incremental revenue growth, strengthen net interest margin, and enhance ROA as integration is completed.

Curious what kind of revenue path, margin expansion, and earnings multiple need to line up to support that fair value at a 7.11% discount rate? The narrative provides a detailed playbook for earnings, profitability, and capital returns that goes far beyond a simple price target headline.

Result: Fair Value of $23.20 (UNDERVALUED)

However, Old Second Bancorp’s heavy concentration in Illinois and exposure to commercial real estate credit trends could quickly challenge this undervaluation story if conditions deteriorate.

Another View: Old Second Bancorp Looks Expensive On Earnings

While the popular Old Second Bancorp narrative leans on a fair value of $23.20 and a modest implied upside, the earnings multiple paints a tougher picture. OSBC trades on a P/E of 13.2x, above the US Banks industry at 11.9x, the peer average at 12.7x, and even its own fair ratio of 12.8x. That gap suggests investors are already paying up for the story, so it is worth considering how comfortable you are with that valuation cushion.

For a closer look at how this earnings based view stacks against other checks, take a look at See what the numbers say about this price — find out in our valuation breakdown.

Next Steps

With mixed signals around Old Second Bancorp's valuation and earnings multiples, it makes sense to review the underlying data yourself and decide where you stand. To weigh both the concerns and the potential positives, start by checking the 3 key rewards and 2 important warning signs

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This article by Simply Wall St is general in nature. We provide commentary based on historical data and analyst forecasts only using an unbiased methodology and our articles are not intended to be financial advice. It does not constitute a recommendation to buy or sell any stock, and does not take account of your objectives, or your financial situation. We aim to bring you long-term focused analysis driven by fundamental data. Note that our analysis may not factor in the latest price-sensitive company announcements or qualitative material. Simply Wall St has no position in any stocks mentioned.