Cuban was cited for "several acts of misconduct" committed after Dallas lost 101-100 in overtime to the Heat in Miami on Sunday night.
Furious with several calls, Cuban went onto the floor to vent directly to official Joe DeRosa. He then stared down and screamed toward commissioner David Stern and a group of league officials, from the court, then the stands. He later used profanity during a postgame session with the media.
The fine was announced hours before the Mavericks played host to the Heat in Game 6 of the NBA finals. Miami led the series 3-2.
Cuban said Monday he was bracing for the fine, his second this postseason. It showed in his reaction to the penalty: "I'm fine with it," he wrote in an e-mail. "Get the humor there. Fine with it."
Cuban has been fined at least $1,455,000 since buying the team in January 2000. The exact total of his punishment tab isn't known because the league doesn't always publicize action against team owners. Cuban says he matches every dollar with a charitable donation.
This also marks the 10th known time that Cuban has been penalized. The biggest fine was $500,000 in January 2002 for comments that included saying he wouldn't hire the league's head of officiating to manage a Dairy Queen.
Since then, the only other acknowledged fine came last month, when he was assessed $200,000 — $100,000 each for going onto the court during a playoff game in San Antonio and for an entry on his blog criticizing the way the league selects officials for the playoffs.
The NBA said it would have no further comment on this matter.
Also Tuesday, Cuban posted a blog entry in response to a column in the Miami Herald that quoted him as saying, "Your league is rigged" during his tirade after Game 5.
"That's a complete insult to the players on the court and the incredible amount of effort they put into preparing for and playing the games," he wrote. "The NBA couldn't rig the games if it wanted to. And it doesn't want to. It's that simple."
He wrote that he hates the idea of any wrongdoing, calling each theory "a business hole I have to work harder to dig us out of."
His solution: Better explanations by the league of what happened and why.
"I think it would help the perception of our game," he wrote. "I think it would help fans better understand not only the rules of the NBA, but also the nuances, strategies and challenges of the game."