Tether Holdings, the issuer of the world's largest stablecoin, is in talks with investors to raise up to $20 billion, according to two people familiar with the matter. This deal could catapul the cryptocurrency company into one of the world's most valuable private companies. Tether hopes to raise between $15 billion and $20 billion in a private placement, representing approximately a 3% stake in the company. Negotiations are in the early stages. Depending on the percentage of shares offered, the deal could value Tether at approximately $500 billion, putting it on par with OpenAI and SpaceX. Its most direct competitor, Circle, had a market capitalization of approximately $30 billion on Tuesday afternoon. Tether is at the forefront of the stablecoin market. Its USDT token, pegged to the US dollar, has a market capitalization of $172 billion, making it the largest stablecoin, while Circle's second-largest stablecoin, USDC, has a market capitalization of approximately $74 billion.