A former New York Islanders hockey team co-owner may seek to withdraw his guilty plea to swindling investors after a U.S. judge said on Wednesday she would sentence the money manager to 20 years in prison.

Michael Tremonte, Stephen Walsh's lawyer, told U.S. District Judge Miriam Goldman Cedarbaum during a hearing in Manhattan that his client had not expected such a long sentence, saying he knew of "not another case even remotely like it where a 20-year sentence has been imposed.

Tremonte asked for an adjournment so that Walsh, a former chief executive of WG Trading Co, could research withdrawing his guilty plea in April to one count of securities fraud.

Under his plea agreement, in which he also agreed to forfeit $50.7 million, Walsh, 70, waived his right to appeal a sentence of 20 years or shorter.

While Cedarbaum granted the adjournment, she said earlier in the hearing the sentence was justified as "many, many people had their money in effect stolen."

"I hope you do realize the gravity of what you have done and you think about it during your time in prison," she said.

The hearing came more than five years after Walsh was first charged over what authorities say was a massive scheme to defraud investors out of out of hundreds of millions of dollars.

Prosecutors said from 1996 to 2009, Walsh and Paul Greenwood, WG Trading Co's chief operating and chief financial officer, solicited investments in what they marketed as a conservative trading program called "enhanced stock indexing."

University foundations, retirement plans, pension funds and others invested more than $7.6 billion, becoming either limited partners in WG Trading or receiving promissory notes, authorities said.

Prosecutors said Walsh and Greenwood, who were both part owners of the New York Islanders National Hockey League team in the 1990's, misappropriated $131 million in investor funds.

Walsh used some of that money to, among other things, finance his children's businesses and pay millions of dollars to his ex-wife, prosecutors said.

To hide the misappropriation and the fact that WG Trading was not profitable, Walsh and Greenwood issued $554 million in promissory notes to investors, prosecutors said.

Greenwood pleaded guilty in 2010 to six charges including securities fraud and conspiracy. He is scheduled to be sentenced Nov. 20.

WG Trading Co and a related entity, WG Trading Investors, have been under the control of a court-appointed receiver after the U.S. Securities and Exchange Commission and U.S. Commodity Futures Trading Commission sought an asset freeze in 2009.

The receiver, Robb Evans, has to date distributed about $854 million to investors, Brick Kane, a deputy to the receiver, said. Total allowed claims by investors are $958 million, he said.

The case is U.S. v. Greenwood, U.S. District Court, Southern District of New York, No. 09-cr-722.