A real-estate firm that has been a favored investment of Sen. Bob Corker, R-Tenn. is under investigation by federal law-enforcement officials for alleged accounting fraud, according to people familiar with the matter.

The FBI and the SEC are focusing their examination of CBL & Associates Properties on whether officials at the Chattanooga, Tenn., company falsified information on financial statements to banks when applying for financing arrangements, the people said. Law-enforcement officials have talked to former CBL employees who allege the company inflated its rental income and its properties’ occupancy rates when reporting those figures to banks, the people said.

The FBI and SEC officials have also separately asked questions about the relationship between the company and Corker, who is close with senior executives at the firm and has made millions of dollars in profits trading the company’s stock in recent years. Authorities don’t believe that Mr. Corker was involved in the company’s potential accounting issues, but they are interested in learning more about the senator’s trading in CBL’s stock, the people said.

They have found no evidence to suggest that Corker has committed wrongdoing.

Micah Johnson, a spokeswoman for Corker, decried the “baseless charges against Senator Corker.”

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