Low oil prices mean trouble for energy companies — and trouble for office properties that rent space to those companies. Several giant loans backed by Houston office buildings may default, according to November’s “Watchlist” report from a Morningstar Credit Ratings, which rates bonds, including commercial mortgage-backed securities (CMBS).

Morningstar added seven loans to properties in Houston totaling $263.5 million to its Watchlist, based on factors like low-occupancy rates, upcoming lease expirations or large amounts of debt.

Houston’s economy is now more diverse than it has been in prior economic downturns for Houston — and that has helped prevent a commercial real estate bust, according to analysis in the Houston Chronicle. “It’s probably bottomed out,” said Morningstar Vice President Steven Jellinek.