PAC Bond(redirected from Planned Amortization Class Bond)
A collateralized mortgage obligation that seeks to protect investors from prepayment risk. PACs do this by setting a schedule of payments; if prepayments of the underlying mortgages exceed a certain rate, the life of the PAC is shortened. If they fall below a certain rate, the life of the tranche is extended. This helps protect investors in case the holders of the underlying mortgages do not pay off their mortgages as expected.