Was reading an WSJ article on how rising rates are affecting balance sheets and had a question about fixed rate bonds.

“Higher yields cause debt prices to fall, reducing the value of trillions of dollars in fixed-rate bonds and loans that banks hold, regardless of whether they intend to sell the assets. In some cases, the losses were equal to or greater than banks’ equity, or the buffer they hold to absorb such hits. “ My question is is a bond has a fixed-rate, how does it lose value if it pays the same rate for the whole period the bank owns the bond?