Impairment
Also called
A signing sits on the balance sheet at its unamortised value. If the player is out of favour, badly injured or plainly worth less than that value, the club writes the difference off. That write-down is an impairment.
Under SCR, impairment is grouped with amortisation in the squad cost definition, so clearing out a costly mistake shows up in the ratio rather than being kept off it.
Impairments are lumpy and unpredictable, which is one reason a single season's ratio can jump without any change in the wage bill.