Tata Sons is the principal investment holding company and promoter of Tata companies. Sixty-six percent of the equity share capital of Tata Sons is held by philanthropic trusts, which support education, health, livelihood generation and art and culture. In 2021-22, the revenue of Tata companies, taken together, was US $128 billion (INR 9.6 trillion). These companies collectively employ over 935,000 people. Each Tata company or enterprise operates independently under the guidance and supervision of its own board of directors. There are 29 publicly-listed Tata enterprises with a combined market capitalisation of $311 billion (INR 23.6 trillion) as on March 31, 2022. Tata group companies include Tata Consultancy Services, Tata Motors, Tata Steel, Tata Chemicals, Tata Consumer Products, Titan, Tata Capital, Tata Power, Indian Hotels, Tata Communications, Tata Electronics, Air India and Tata Digital.