From what I found and know:

Tether is owned by Tether Holdings Limited, a company based in the British Virgin Islands, which is a subsidiary of iFinex Inc., the parent company of the Bitfinex cryptocurrency exchange. Key figures behind Tether include Giancarlo Devasini, who is a controlling shareholder, and Jan Ludovicus van der Velde, who serves as CEO. Paolo Ardoino, the current CTO, will take over as CEO in December 2023. Tether is the largest stablecoin by market capitalization, providing a digital representation of fiat currencies