Third Coast Bank Merger
Third Coast Bancshares, Inc. and Keystone Bancshares, Inc. Announce Definitive Merger Agreement
Once completed, Combined Total Assets to Exceed $6 Billion
HOUSTON and AUSTIN, TX – October 22, 2025 – Third Coast Bancshares, Inc. (“Third Coast”) (NYSE & NYSE Texas: TCBX), the parent company of Third Coast Bank, and Keystone Bancshares, Inc. (“Keystone”), the parent company of Keystone Bank, SSB (“Keystone Bank”), today jointly announced the signing of a definitive merger agreement pursuant to which Third Coast will acquire Keystone in a stock and cash transaction valued at approximately $123 million based on Third Coast’s closing stock price as of October 21, 2025. Once the transaction is completed, the combined company will have pro forma total assets in excess of $6 billion.
Pursuant to the terms of the merger agreement, the combined company will operate under the Third Coast name and brand. The partnership presents a unique opportunity to combine two culturally aligned community banks and strengthen Third Coast’s position in the greater Austin market. Keystone Bank, headquartered in Austin, Texas, operates two branches in the Austin market, one branch in Ballinger, Texas, and one loan production office in Bastrop, Texas.
Read The Full Press Release Here
Stay up-to-date with the merger of Keystone Bank and Third Coast Bank by visiting our On The Horizon page frequently for the latest announcements.
What to Expect & Key Dates
We are excited to begin officially transitioning Keystone Bank customers to Third Coast Bank. We know this will bring change, and we want you to feel informed, comfortable, and confident about what's ahead. Our team is here to help every step of the way. If you have questions or need assistance, please don't hesitate to reach out. We're committed to making this transition as smooth and seamless as possible.
As we move into June, we have begun sending important communications to our Keystone Bank customers outlining changes associated with our upcoming merger. A physical copy of these communications is being sent via the U.S. Postal Service, with a reminder being sent via email to customers that includes Important Dates at a Glance, Personal Banking Account Conversion Guide, and Business Banking Account Conversion Guide.
Your conversion weekend timeline begins on Friday, July 17, 2026. We will officially convert to Third Coast systems on Monday, July 20, 2026.
- All Keystone Bank branches will close at 3:00 PM CT on Friday, July 17, and open at regular business hours on Monday, July 20.
- All Keystone Debit Cards and Digital Wallets will operate normally over the weekend through Sunday, July 19, until 11:59 PM CT. Debit cards will be deactivated at midnight (12:00 AM CT). Please set up your Third Coast Bank debit card on or before Monday, July 20.
- Keystone Online and Mobile Banking access will end at 4:00 PM CT on Friday, July 17. As a result, you must begin logging in to Third Coast Online and Mobile Banking on Monday, July 20, at 8:00 AM CT.
Your Personal Banking Account Conversion Guide
Personal Account Conversion Guide
Your Business Banking Account Conversion Guide
This guide provides important details about your business accounts. Inside, you'll find specifics about your bank account transition and answers to many common questions. Click the link below to view the full guide.
Business Account Conversion Guide
Digital Banking Guides ** Coming Soon **
Retail and Treasury Management Digital Banking Guides will be available by the beginning of July. Monitor your emails for your specific communications and check back here for additional updates.
Coming soon!
Frequently Asked Questions
Please refer to the appropriate conversion guides in the Customer Communications tab on the left for answers to any frequently asked questions.
Use this calculator to determine your projected earnings from our Keystone Rewards Checking account. Move the sliders or type in the numbers to see your potential rewards.
- Estimated Annual Rewards $0
- Estimated monthly interest earned* $0
- Monthly ATM fees refunded**$0
This calculator compares the costs of buying or leasing a vehicle. There are three sections to complete, and you can adjust and experiment with different scenarios.
- Net cost of buying $0
- Net cost of leasing $0
A fixed-rate, fixed-term CD can earn higher returns than a standard savings account. Use this calculator to get an estimate of your earnings. Move the sliders or type in numbers to get started.
- Total value at maturity $0
- Total interest earned $0
- Annual Percentage Yield (APY)0.000%
Whether it's a down payment, college, a dream vacation...a savings plan can help you reach your goal. Use the sliders to experiment based on length of time and amount per month.
- Monthly deposit needed to reach goal $0
This calculator can help you get a general idea of monthly payments to expect for a simple loan. Move the sliders or type in numbers to get started.
- Estimated monthly payment $0
- Total paid $0
- Total interest paid $0
Keystone Rewards Checking*
| Tier | Interest Rate | Annual Percentage Yield |
|---|---|---|
| 0 - $50,000 | 4.5537% | 4.65% |
| $50,000+ | 0.50% | 1.88% to 4.65% |
| Qualifications not met | 0.05% | 0.05% |
Qualifications
Earning your rewards is as simple as using the free services that come with your account. Enrollments must be in place and all of the following transactions and activities must post and settle to your Keystone Rewards Checking® account during each Monthly Qualification Cycle:
- At least 1 ACH credit or ACH payment transaction
- At least 12 debit card purchases, each greater than or equal to $3.50
And if you don’t meet your qualifications during a cycle, your free account will still earn our base rate. Then you can get back to earning your full rewards the very next month.
Keystone Rewards Savings*
| Tier | Interest Rate | APY |
|---|---|---|
| 0 - $100,000 | 3.8320% | 3.90% |
| $100,000+ | 0.50% | 2.20% to 3.90% |
| Qualifications not met | 0.05% | 0.05% |
Qualifications
Qualifying for your Keystone Rewards Checking or Keystone Cash Back Checking® rewards automatically qualifies you for the highest Keystone Rewards Savings® rate, too. Enrollments must be in place and all of the following transactions and activities must post and settle to your Keystone Rewards Checking or Keystone Cash Back Checking account during each Monthly Qualification Cycle:
- At least 1 ACH credit or ACH payment transaction
- At least 12 debit card purchases, each greater than or equal to $3.50
It's no problem if you miss a qualification cycle. Both accounts are still free and earn our base interest rate. And you can get back to earning rewards the very next month you qualify.
