At age 67, Thomas C. Davis should be enjoying all the perks of a long and distinguished career at the pinnacle of Wall Street and the Texas business elite. These include golfing at the prestigious Dallas Country Club and Preston Trail Golf Club, where he was a member; trips to Las Vegas and golf tournaments on the private jet he co-owned; and fractional ownership of two professional sports teams, the Texas Rangers and the Dallas Stars.

What he faces instead is the prospect of 20 years or more in federal prison and millions of dollars in fines.

Last month, Mr. Davis pleaded guilty to 12 felonies for a brazen insider trading scheme in which he leaked a stream of confidential information about the Dallas-based Dean Foods while he served as the company’s chairman.

When questioned by agents from the Federal Bureau of Investigation in 2014 and lawyers from the Securities and Exchange Commission last year, he lied, compounding his securities fraud by committing perjury. And after the F.B.I. agents left, he took a prepaid cellular phone he had used to leak the information and threw it into a creek near his Dallas home, destroying evidence and obstructing justice.