Bond Price and Interest Rate Relationship

If you take only one lesson from the Fixed Income section, let it be this: Bond prices and interest rates have an inverse relationship. When market interest rates rise, existing bond prices fall.¹ When market interest rates fall, existing bond prices rise.²

In the 2026 market, this "seesaw" is the most important mechanical force driving your portfolio's value.

1. Why the Inverse Relationship? (The "Alternative" Test)

To understand why this happens, you have to think like a buyer in the secondary market. Imagine you own a bond that pays a 5% coupon.

• Scenario A: Interest Rates Rise to 6%

New bonds are now being issued with a 6% interest rate. No one will buy your "old" 5% bond at full price (Par) because they can get 6% elsewhere.3 To find a buyer, you must drop your price-selling at a discount-until the total return for the new buyer equals the 6% they could get elsewhere.

• Scenario B: Interest Rates Fall to 4%

Now, your 5% bond is a "prize." New bonds only pay 4%, so investors will bid up the price of your bond to own that higher interest stream. Your bond will trade at a premium (above par) until its effective yield matches the 4% market rate.

2. The Role of the Fixed Coupon

The reason the price must move is that the Coupon Payment is fixed.

• A ₹1,000 bond with a 5% coupon will pay exactly ₹50 every year until it matures.
• Since the ₹50 can't change, the market price is the only "lever" that can move to ensure the bond's total return (Yield) stays competitive with the rest of the market.⁵

3. Sensitivity: Duration and Maturity

Not all bonds react to rate changes with the same intensity. The degree of price change depends on two main factors:

1. Time to Maturity: Longer-term bonds (e.g., 30 years) are much more sensitive to rate changes than short-term bonds.⁶ This is because a 1% rate hike affects 30 years of future payments rather than just two or three.
2. Coupon Rate: Bonds with lower coupons are generally more sensitive to interest rate changes than those with higher coupons.

4. Summary: The Seesaw Cheat Sheet