Trailing Twelve Months average — returns the mean of the last 4 quarterly values. Useful for metrics like average quarterly margin or average inventory.
Formula: TTM Avg = (Q(n) + Q(n-1) + Q(n-2) + Q(n-3)) / 4
Used by financial modellers to smooth seasonal volatility. Rather than looking at a single quarter in isolation, the TTM average gives the normalised quarterly run-rate for the past year.