Steven A. Cohen proved to be a stickler for the letter of the law when it came to paying the criminal penalty imposed on his former hedge fund as part of its guilty plea on insider trading charges.

On April 10, Judge Laura Taylor Swain of Federal District Court in Manhattan gave Mr. Cohen's SAC Capital Advisors up to 90 days to pay the $900 million penalty, part of an overall $1.2 billion criminal settlement reached with prosecutors last November. On Tuesday, the 90th day since Judge Swain accepted the firm's guilty plea, Mr. Cohen's firm made that payment in four installments, according to court records.