Billionaire investor Mark Cuban has publicly criticized Vice President Kamala Harris' proposal to tax unrealized capital gains, warning it could 'kill the stock market' and negatively impact private equity and startup companies. While Cuban supports Harris, he insists she will not implement this tax plan, describing it as a 'starting point' for broader economic discussions. Harris has proposed a 28% capital gains tax to address wealth inequality, but Cuban argues that such a move could lead to long-term economic consequences. During a contentious CNBC interview, Cuban shared his concerns, emphasizing his frequent consultations with Harris' campaign. Despite his reservations, Cuban defended Harris' intent to tax the wealthy 'fairly,' although skepticism remains about her campaign's messaging to donors and the public.