Cuban confirmed the fine through his Twitter account shortly before the league announced its punishment for Cuban's remarks which violated the league's anti-tampering rules.
"For those of you who care about these things, NBA just fined me 100k for comments regarding another teams' players," Cuban wrote.
NBA rules prohibit team officials from commenting on potential free agents until the market opens on July 1.
Asked on Tuesday night before the draft lottery about what teams were allowed to do, NBA commissioner David Stern said: "Come July 1, just about everything goes. Before July 1, nothing goes."
Earlier this week in a CNNMoney.com interview, Cuban was asked he if is interested in signing James. Cuban said he is hopeful that James will try to force a sign-and-trade, which would give the Mavericks an opportunity to acquire him.
"Come July 1st, yeah, of course, anybody would be interested in LeBron James," Cuban said in the interview. "And if he leaves via free agency, then it's going to be tough. If he does like I'm guessing, hoping he will, which is say, 'I'm not going to leave the Cavs high and dry,' if he decides to leave -- there's still a better chance he stays -- then he'll try to force a sign-and-trade and that gives us a chance."
The league more or less slapped Cuban on the wrist considering he and the club faced a maximum fine of $5 million and the possibility of not being able to pursue James in the case he does become a free agent. The league sent a memo to all 30 teams in 2008 directing team officials to decline comment about potential free agents when asked by the media.
The league also fined Phoenix Suns president of basketball operations Steve Kerr $10,000 for comments he made regarding James on a radio show on May 14. Kerr joked that he would like to sign James for the mid-level exception, "About five-and-half million, I think he'll take it. Don't you think?" Kerr said.
Kerr was then asked where he thought James would end up next season. Kerr said, "I have no idea. I want him to stay in Cleveland. I think that's good for sports when you've got players you connect to over a long period of time, so I hope he stays."
A Suns spokesperson said the team would have no further comment on the matter.
Jeff Caplan covers the Mavericks for ESPNDallas.com. You can follow him on Twitter or leave a question for his weekly mailbag. Information from ESPNLosAngeles.com's Ramona Shelburne and The Associated Press contributed to this report.