shootingstar

When the coupon rates are close to yields - eg. coupon rate 6% and yield 6.001%.

If the two rates are very different the statement may not hold true - (the ceteris paribus thing!). For instance if the yield is much higher the bond price of the option fee bond could actually be depressed to a value lower than the bond with a the call option. Remember the callable bond price is (other things being constant) less because of the risk of the call to the investor.

I am not sure whether this helped?