The penalty was the 14th the league has announced against Cuban, who has been penalized about $1.5 million over the years and suspended from three games.

Cuban went onto the court at halftime to complain to J.R. Smith about an elbow he saw the Nuggets player throw at the Mavs' Antoine Wright. Denver coach George Karl criticized Cuban following the game, then again the next day at practice, for coming onto the court and yelling at one of his players.

The league informed teams before the 2006-07 season that club personnel other than coaches was prevented from going into huddles or the floor - a ruling Cuban felt was aimed at him.

There was no action against Smith.

Cuban didn't respond to an e-mail request for comment, but wrote about the fine under an item titled "Me and JR Smith" on his blog.

After beginning the letter by apologizing to Smith for not accepting his offer of a signed pair of sneakers, Cuban continued: "The NBA tells me a tech should have been called on you for throwing the elbow and that I should pay a 25k dollar fine because owners aren't supposed to get mad. Ever.

"In the spirit of the joy of my getting fined and your not getting the tech, have the Nuggets PR folks contact the Mavs PR folks and I will donate 25k to the charity of your choice.

"Unless of course your coach thinks that the wrong thing to do, or the NBA says I can't because it would be a violation of a rule. In which case, I will find a charity that I think you would like and make the donation in your name."

Cuban was angered at the end of the game after a disputed foul called on Jason Terry led to the go-ahead free throws by Chauncey Billups with 2.2 seconds left. The Mavericks felt that Billups created the contact.

A frequent critic of the officiating, Cuban was fined twice during the 2006 playoffs, including after Game 5 of the NBA finals, for his conduct.