COMPANION TRANCHE

Tranche seen in a planned amortization class (PAC), targeted amortization class (TAC), and collateralized mortgage obligations (CMOs) assuming variable prepayment rates. It is designed to support the principal PAC tranche, which takes the first priority in receiving principal and interest payments to give its investors more stable and predictable cash flows. If the rate of prepayments is different from the assumptions made at the CMO was issued, the companion tranche takes the difference. Also called support tranche.