A former Goldman Sachs Group Inc. fixed-income research associate was sentenced to more than four years in prison after pleading guilty last year to criminal charges in a series of insider-trading schemes that prosecutors said netted more than $6 million in illicit profits.

At a hearing yesterday, U.S. District Judge Richard Holwell in Manhattan sentenced Eugene Plotkin, of Rockland County, N.Y., to 57 months in prison to be followed by two years supervised release. He also ordered Plotkin to pay a $10,000 fine and to forfeit $6.7 million.

“I feel immense remorse regarding the lapse in judgment and the actions that brought me before you today,” Plotkin said prior to sentencing.

Plotkin, 28 years old, pleaded guilty to conspiracy and eight counts of insider trading in August. He had faced 57 months to 71 months in prison under federal sentencing guidelines. He is expected to report to prison on March 14.

The forfeiture is expected to come from money already frozen by the government in accounts in America and overseas, including funds from other participants in the scheme, Plotkin’s lawyer, Edward Little, said.

Assistant U.S. Attorney Helen Cantwell said the government had frozen about $4 million held in accounts in America.

Prosecutors have alleged that Plotkin and a former analyst in Goldman Sachs’ fixed-income division, David Pajcin, orchestrated an insider-trading ring that generated at least $6.7 million in illegal proceeds.

Pajcin, who is cooperating with the government, has pleaded guilty to criminal charges in the matter and is awaiting sentencing.

However, Mr. Little, Plotkin’s lawyer, disputed the government’s assertion during yesterday’s hearing that Plotkin was an “equal partner” with Pajcin.

“[Plotkin] was used like the others,” Mr. Little said.

Some of the improper trades in Reebok were made in an account in the name of Pajcin’s aunt, a retired Croatian seamstress, prosecutors said.