What is the difference between spot and forward multiples, and which should you use?

current market cap / EV against LTM EBITDA — a trailing multiple. Forward multiple (NTM, FY+1, FY+2): market cap / EV against forecast EBITDA — a forward multiple. For growth companies, forward multiples are lower than trailing (because EBITDA grows). IB standard: the NTM multiple is the primary benchmark. Rationale: the market prices in future cash flows, so a forward multiple is 'apples-to-apples'. LTM only as a sanity check. Pitfall: the NTM multiple rests on consensus EPS forecasts — after recent earnings misses or guidance cuts, consensus can be stale.