Prosperity Bancshares, Inc. (PB) and Stellar Bancorp, Inc. (STEL) announced a blockbuster merger alongside their quarterly earnings reports Wednesday, and the market's reaction tells you everything about how investors view banking consolidation deals these days.

The Deal Structure

Under the agreement, Prosperity will pay a combination of 0.3803 shares of its common stock plus $11.36 in cash for each share of Stellar common stock. Based on Prosperity's closing price of $72.90 on January 27, 2026, that values the entire transaction at roughly $2.002 billion.

The boards of both companies have unanimously approved the deal, which is expected to close in the second quarter of 2026 once it clears the usual regulatory hurdles and closing conditions.

David Zalman, Senior Chairman and CEO of Prosperity, made the strategic case pretty clear: "The combination of our companies will create the second largest bank by deposits headquartered in Texas with over 330 banking centers. Together, our increased scale better positions us to invest in future opportunities and serve our customers."

He added that "Stellar and its predecessors have been serving the Houston and Beaumont, Texas areas for many years. This is a rare opportunity to significantly enhance our presence in the Houston area, a market with a diverse economy that is continually attracting investment and has a growing population."

Translation: Houston is booming, and Prosperity wants a bigger piece of it.

The Earnings Picture

Alongside the merger announcement, Prosperity Bancshares reported fourth quarter earnings of $1.46 per share, just edging past the analyst consensus of $1.45. Revenue came in at $317.7 million, slightly below the consensus estimate of $318.5 million.

Meanwhile, Stellar Bancorp reported quarterly earnings of 51 cents per share, hitting consensus expectations right on the nose. Revenue totaled $108.9 million, topping the consensus estimate of $107.6 million.

On the balance sheet front, Stellar Bancorp ended December 31 with cash and cash equivalents of $419.5 million, while Prosperity Bancshares reported cash and due from banks of $1.75 billion.

Market Reaction

Here's where it gets interesting. Despite beating earnings estimates and announcing a major expansion, Prosperity Bancshares shares dropped 9.03% to $66.31 at the time of publication Wednesday. Stellar Bancorp shares, on the other hand, jumped 11.03% to $36.45.

That's classic acquisition math for you: the acquiring company's shareholders worry about overpaying and integration risks, while the target company's shareholders celebrate the premium they're getting. The deal creates a powerhouse Texas bank, but investors will be watching closely to see if the promised synergies materialize once the merger closes later this year.