Mehli K. Mistry, the veteran Tata Group insider who worked alongside the late Ratan Tata for decades and later became one of the executors of his will, has resigned as a director of RNT Associates Pvt. Ltd., the former Tata Sons chairman's personal investment company, according to media reports.According to reports, Mistry submitted a resignation letter dated June 30 to the board of RNT Associates, stating that he would step down as a director with effect from July 1. He reportedly cited "preoccupation with my other commitments" as the reason for his resignation.Neither RNT Associates nor Mistry has publicly commented on the development.Incorporated in 2009, RNT Associates serves as the principal investment vehicle through which Ratan Tata made investments in his personal capacity. According to public investment databases and media reports, the investment office has backed several of India's best-known startups, including BlueStone, Ola Electric, CarDekho, Moglix, Urban Company, Lenskart, Cure. fit, CashKaro and FirstCry.