The Andover State Bank has purchased a corporate bond from the Tristate Manufacturing Company that has $15$ years to maturity and has a coupon rate of $6\mathrm{.}25\%.$ Market interest rates have recently declined to $5\mathrm{.}25\%$ and the Andover State Bank is worried that the Tristate Manufacturing Company will exercise its right to retire the bonds early, and issue new corporate bonds with a lower coupon rate. What type of risk is the Andover State Bank worried about?