When it came to putting the squeeze on Peco Energy Co., former State Sen. Vincent J. Fumo and his staff never missed an opportunity.

According to testimony yesterday in Fumo's federal corruption trial, he and his aides saw such a chance in early 2002 when it was time for Peco to pay its biggest single installment to a nonprofit that Fumo backed.

The sum at issue was $10 million, payable to the nonprofit Citizens' Alliance for Better Neighborhoods, which a Fumo aide headed.

In January 2002 Peco wanted to give the money to Fumo personally.

The trouble was that Fumo was vacationing in Florida.

His legislative counsel, Christopher Craig, was understanding of Peco's wishes. In an e-mail to Peco, he advised the utility that it was "more than reasonable for the company to want to present to him directly the money."

Craig had a solution. Fumo could do a ceremony in March and, in the meantime, Peco should tack onto its donation one month's interest at the prime rate.

In court yesterday, former Peco executive Thomas P. Hill didn't sound all that happy about this request. He testified that he was surprised the senator's office was being "so precise" about the money.

At the time, though, Hill e-mailed Craig back to say the idea "Sounds good let's set up a date . . . Plan to be there."

Peco ultimately gave Citizens' Alliance one check for $10 million and another for $39,583.33, or a month's interest at a prime rate of 4.75 percent.

As for the ceremony, it happened in private. Neither Fumo nor Peco disclosed its donations.