From Hard Drop - Tetris Wiki
The Tetris Company, or TTC, currently own and license Tetris rights through Elorg. Henk Rogers and Alexey Pazhitnov established the company in 1996, when the ten year Russian license expired. With the creation of TTC, unlicensed made games felt pressure, since TTC had to protect its trademark rights. Licensed games would start to follow a Tetris Guideline maintained by TTC and include TTC's "Authentic Tetris Game" seal. During the summer they updated their page and mentioned changing their name to Tetris Holding Company. The update was temporary and the site reverted back soon after. In an interview with Pajitnov, he confirmed this as well as mentioned finishing the contract with Elorg. Most recent games confirm this.
Sheffield, Brandon. "Alexy Pajitnov, Master of Shapes." Game Developer Sep. 2006: 10 .