More than $1 trillion in U.S. real estate debt from the last decade’s property boom is starting to come due as oil prices stagnate, squeezing property owners in cities and towns centered around the energy business. The 50 percent plunge in crude values since June is already dragging down property prices in Texas, according to Green Street Advisors LLC. Real estate investors are adjusting their underwriting across the state as they gird for contraction at energy companies, demanding higher yields on their investments, the property-research firm said. “It is going to be harder and more costly for borrowers in energy hubs to refinance loans in today’s environment, versus when oil was $100 a barrel,” Andy McCulloch, an analyst at Newport Beach, California-based Green Street, said in an e-mail. “Just how much harder or costly will depend.” Even as U.S. commercial real estate values surge past records set in 2007, […]