🧾 What This Document Is

This is a Form 425 filing from Stellar Bancorp (ticker: STEL). Think of it as a formal update submitted to the SEC about a major corporate event—specifically, a pending merger. This filing announces that a critical final regulatory hurdle has been cleared, paving the way for the deal to move forward.

🏢 Meet the Two Banks

In simple terms, this merger is about two Texas-based banks joining forces.

• Stellar Bancorp, Inc. (STEL) is the smaller of the two, headquartered in Houston. Its main business is Stellar Bank, which provides commercial banking services to small and medium-sized businesses and individuals in key Texas markets like Houston and Dallas.
• Prosperity Bancshares, Inc. is the larger, acquiring bank. Also based in Houston, it's a major regional player with $38.463 billion in assets as of December 31, 2025. It operates 312 banking locations across Texas and Oklahoma, offering a full range of personal and business banking services.

👉 The Big Picture: This deal is a classic "bigger bank buys smaller bank" scenario, aiming to create a more extensive regional banking network.

💰 The Financial Context

While this specific filing doesn't contain new financial results, it exists within the context of the merger agreement first announced on January 27, 2026. The ultimate financial terms—how many shares of Prosperity stock Stellar shareholders will receive—were set in that original agreement and will be detailed in the proxy statement sent to shareholders.

🚀 Key Milestone: The Green Light

The core news in this filing is regulatory approval. The companies announced they have now received all necessary regulatory waivers and approvals to complete the merger. This includes:

• A waiver from the Federal Reserve Bank of Dallas.
• Approvals from the Federal Deposit Insurance Corporation (FDIC) and the Texas Department of Banking.

👉 Why it matters: Mergers between banks are heavily regulated. Getting these approvals is a major "go/no-go" checkpoint. With them in hand, the deal can proceed to the final shareholder vote.

📦 What Happens Next: The Final Steps

The path to completion is now clear and follows a set timeline:

1. Shareholder Vote: A special meeting for Stellar shareholders to vote on the merger is scheduled for May 27, 2026.
2. Expected Completion: If shareholders approve, the merger is expected to be finalized on or about July 1, 2026.
3. Bank Integration: Following the parent company merger, Stellar Bank will legally merge into Prosperity Bank.

👉 Key Detail: The deal is still subject to shareholder approval and other "customary closing conditions." This filing marks the finish line coming into view, but the race isn't over yet.

🔮 What This Signals for the Industry

This merger reflects a continuing trend of consolidation in the regional banking sector. By combining, the new, larger Prosperity can achieve greater scale, potentially leading to cost savings and a stronger competitive position against both bigger national banks and smaller community banks in the Texas and Oklahoma markets.

🧠 The Analogy

Think of this merger like a wedding. The couple (Prosperity and Stellar) announced their engagement back in January (the merger agreement). Today's filing is like announcing they've both gotten their marriage license and completed all the pre-wedding legal requirements. The big ceremony (the shareholder vote) is set for late May, and the official honeymoon (the merged operation) is planned to start around July 1st.

🧩 Final Takeaway

Stellar Bancorp has cleared the last major regulatory hurdle for its acquisition by Prosperity Bancshares. With all approvals secured, the focus now shifts entirely to a shareholder vote on May 27, 2026, which is the final condition before the merger closes around mid-2026, creating a significantly larger regional bank.