Blackstone Infrastructure, an investment giant with $600 million in assets under management, has agreed to buy publicly traded TXNM Energy in a debt-and-stock deal valued at $11.5 billion.

TXNM Energy is the parent company of Lewisville-based Texas New Mexico Power (TNMP), which supplies electricity to more than 270,000 homes and businesses throughout Texas. Its Houston-area service territory includes Alvin, Angleton, Brazoria, Dickinson, Friendswood, La Marque, League City, Sweeny, Texas City and West Columbia.

Once Blackstone Infrastructure wraps up the deal in the second half of 2026, Albuquerque, New Mexico-based TXNM will no longer be a public company. But TNMP’s headquarters will remain in Texas and its rates will continue to be set by the Public Utility Commission of Texas. TNMP was founded in 1934.

Blackstone Infrastructure is affiliated with investment powerhouse Blackstone Inc., which has $1.2 trillion in assets under management and is the world’s largest investment manager.

“TNMP has done an excellent job of meeting its customers’ growing demand for electricity and supporting the communities it serves,” Sean Klimczak, Blackstone’s global head of infrastructure, said in a news release. “We look forward to utilizing our long-term investment commitments to support TNMP as they continue on this path of high-demand growth across Texas.”

During TXNM’s fourth-quarter earnings call in February, Chairwoman and CEO Patricia Vincent-Collawn said the company’s five-year Texas capital investment plan had grown by more than $1 billion.

“Our future is so bright with these increased investment levels that we are now targeting earnings growth of 7 percent to 9 percent through 2029,” Vincent-Collawn said.

“Our financial expectations are driven by the continued expansion of grid infrastructure supporting growth and reliability in our Texas service territory,” she added.

In 2024, TXNM reported revenue of $1.96 billion, up 1.7 percent from the previous year.