Tether Holdings SA, issuer of the world’s largest stablecoin, is in talks with investors to raise as much as $20 billion, a deal that could propel the crypto firm into the highest ranks of the world’s most valuable private companies. Most Read from Bloomberg The El Salvador-based company is seeking between$15 billion and $20 billion in exchange for a roughly 3% stake through a private placement, according to two people familiar with the matter. Another person involved in the process cautioned that th ...