New York (AFP) - A quick chat and a two-minute drive is all it took for an American cab driver to be tipped nearly $1,000.

Oumar Maiga, a night-shift driver from Philadelphia, was so stunned he waited a month for the credit card transaction to clear, convinced the mystery benefactor might claim a mix-up.

His boss, Freedom Taxi owner Everett Abitbol, said it was the largest tip he had ever seen for such a small fare: $4.31 for a brief, late-night pick-up in downtown Philadelphia.

Maiga picked up the anonymous passenger and the two struck up a conversation.

The two exchanged pleasantries about the driver's busy schedule in the run up to Christmas and the customer said he knew being a cabbie was a tough job, Abitbol told AFP.

"He said, 'hey, I'm going to take care of you' and when our driver looked down he said 'sir, I think you made a mistake' but he said 'that's what I want to give you, I know what I did'."

Abitbol said the tip couldn't have happened to a nicer man, adding that Maiga had been with the company since it opened in 2011.

"He's a family guy, a very, very nice driver," said Abitbol. "You can always rely on him."