Bernard J. Ebbers, who was imprisoned in 2006 after his conviction in one of the biggest American frauds of the 20th century, will soon be free after serving a little over half of a 25-year sentence.

Mr. Ebbers, also known as Bernie, was sent to federal prison after carrying out an $11 billion accounting fraud as chief executive of the telephone company WorldCom. He was granted a compassionate release by a federal judge in New York, Valerie E. Caproni, a spokesman for the United States attorney’s office in Manhattan said on Wednesday. The spokesman did not know when Mr. Ebbers would be freed.

“We are grateful for the ruling and hope Bernie gets some peaceful and loving time with his friends and family,” one of his lawyers, Reid H. Weingarten, said in an email.

Mr. Ebbers, now 78, steered WorldCom through a series of acquisitions that took it from a small telephone company in Mississippi to a juggernaut competing with AT&T and other national long-distance carriers. But the company’s apparent success, which drove its stock price to Olympian heights and contributed to a bubble in telecommunications stocks, was a fantasy.