Corporate Bond Spread Over G-Sec
The difference in yield between a corporate bond and a comparable-maturity government security (G-Sec), representing the credit risk premium demanded by investors for holding a private issuer's debt relative to the sovereign, with spreads widening for lower credit ratings (AAA, AA, A, BBB).
The corporate bond spread over G-Sec (also called the credit spread) was the fundamental measure of the additional yield an investor demanded for accepting credit risk beyond the sovereign baseline. In Indian fixed income markets, the G-Sec yield served as the risk-free rate, and all other debt instruments were priced as a spread above this baseline.
The spread was determined by multiple factors: the issuer's credit rating (AAA-rated issuers commanded spreads of approximately 40-80 basis points over comparable G-Secs for five-year paper, while AA-rated spreads were typically 80-150 bps and A-rated spreads could be 200-400 bps or more depending on the issuer); the liquidity premium (bonds from smaller issuers with lower trading volumes commanded an additional illiquidity premium); and macro conditions (during credit stress events such as the NBFC liquidity crisis of 2018 or the Franklin Templeton debt fund crisis of 2020, spreads across rating categories widened sharply).
CRISIL, ICRA, CARE, and India Ratings (Fitch affiliate) maintained historical corporate bond spread data and published periodic reports on credit spread trends. CCIL's NDS-OM data was supplemented by BSE Bond (India INX) and NSE bond platform data to compute market-observed spreads for individual issuers.
For mutual fund investors, the corporate bond spread was directly relevant in understanding the return premium being earned by credit risk funds, corporate bond funds, and short-duration funds relative to pure gilt or government-backed funds. Higher portfolio spreads implied both higher expected returns and higher credit risk concentration.
Spread duration (sensitivity of a bond's price to changes in credit spread) was a key risk metric used by fixed income portfolio managers alongside modified duration (which captured interest rate risk). A portfolio with high spread duration was disproportionately affected by spread widening in credit-stress periods even if underlying G-Sec yields were unchanged.