The Tata Group has retained its place as the country's most valuable brand at USD 21 billion, while the total worth of top-100 Indian brands now stands at USD 92.6 billion, says a new study. State-run insurance behemoth LIC is ranked second with a brand value of USD 4.1 billion, followed by public sector bank SBI (USD 4 billion), Bharti Airtel (USD 3.8 billion) and Reliance (USD 3.5 billion).