My one example here is consistent with other's observations about the range of possible future outcomes for bonds. (mindfullyinvesting.com)
The principal of these mortgages was guaranteed by Ginnie Mae, but not the risk that borrowers pay off the principal balance early or opt to refinance the loan, a set of possible future outcomes known as «prepayment risk.» (en.wikipedia.org)
The OPM depends on key assumptions regarding the volatility and time to a liquidity event, but does not require explicit estimates of the possible future outcomes. (sec.gov)