An issuer can't always guard against termination of a swap before final maturity, but limited two-way payments and other special terms and can make the situation less of a headache.
At any time, the fixed-rate side of the transaction may be above or below the current market rate for swaps. The market value of the swap is based on the difference between the current rate and the rate on the swap. The higher the rate on the swap is above current rates, the more valuable the swap is to the side receiving the fixed-rate payment. If the rate is below current rates, the swap is valuable to the side receiving the floating-rate payments.