# Mark Cuban **Mark Cuban** is an American billionaire entrepreneur. He made his first fortune when Yahoo bought his internet-radio company Broadcast.com. He owned the NBA's Dallas Mavericks for more than two decades and was a longtime investor on ABC's *Shark Tank*, a seat he gave up after the 2024–25 season. He now runs Mark Cuban Cost Plus Drug Company, an online pharmacy that sells generic drugs at a flat markup over cost. He's on the map as the most prominent anti-Trump voice inside the [[Tech Right Group Chats]]. In 2024 he was one of [[Kamala Harris]]'s best-known business surrogates. In 2025, according to Semafor, he was arguing with [[Joe Lonsdale]] and [[Ben Shapiro]] in Chatham House, the largest of the Signal groups. By 2026 he was at the White House promoting Trump's drug-pricing program. He shows how the chats worked as a debate club with a visible opposition, and how hard it is for even a vocal critic to stay outside the administration's orbit. ## Business Cuban sold Broadcast.com to Yahoo in 1999 and bought the Mavericks in 2000. In December 2023 he sold a majority stake in the team to [[Miriam Adelson]] and her son-in-law Patrick Dumont, at a reported valuation of about $3.5 billion. He kept a minority share. He co-founded Cost Plus Drugs in 2022 with Alex Oshmyansky. It sells drugs at a flat 15% markup plus pharmacy and shipping fees, and has become his main focus. ## Politics Cuban has described himself as an independent. In 2024 he campaigned for Harris, including at rallies where he attacked Trump's proposed tariffs as a tax on everybody. Fortune reported he gave her no money and didn't want a cabinet job. After the election he said he wouldn't support another Harris run. In April 2026 he ruled out running for president himself. In 2026 he also loudly opposed California's proposed billionaire tax, warning that he would steer new companies away from the state if it passed. ## Inside the group chats Semafor reported that Cuban was a participant in Chatham House, the large Signal group whose members also included Lonsdale, Shapiro and [[Tucker Carlson]]. In one week of chats Semafor described, Cuban and Lonsdale argued over affirmative action, and Cuban and Shapiro discussed culture and work ethic. A podcast debate between Cuban and [[Vivek Ramaswamy]] began in a chat. His presence let the network describe itself as a place for real argument across party lines, even as most of its weight moved toward Trump. ## Working with Trump (2026) On May 18, 2026, Cuban appeared at a White House health-care affordability event with [[Donald Trump]] to promote cheaper prescription drugs, linking Cost Plus Drugs with the administration's TrumpRx effort. See [[Most-Favored-Nation Drug Pricing Deals]]. Trump joked from the stage that Cuban's Harris endorsement had been a big mistake. Asked about his 2024 politics, Cuban said he wasn't "going into my politics at all," and that "Democrats want cheaper medications, too." ## Why it's on the map - **The opposition inside the chats.** He's the best-known anti-Trump member of the network Semafor credited with shaping Silicon Valley's turn toward Trump. - **Pragmatism or co-optation.** His 2026 drug-pricing partnership shows how the administration draws in business critics around specific policy wins. - **The independent billionaire.** He keeps a large public platform outside both parties while staying involved with both. ## Connections - [[Tech Right Group Chats]] · [[Joe Lonsdale]] · [[Ben Shapiro]] · [[Tucker Carlson]] · [[Vivek Ramaswamy]] - [[Kamala Harris]] · [[Donald Trump]] · [[Most-Favored-Nation Drug Pricing Deals]] - [[Miriam Adelson]]