undervaluing

verb (used with object), un·der·val·ued, un·der·val·u·ing.

1. to value below the real worth; put too low a value on.
2. to diminish in value; make of less value.
3. to have insufficient regard or esteem for; hold too low an opinion of.

verb -values, -valuing or -valued

1. (tr) to value at too low a level or price

v.1590s, “to rate as inferior in value” (to), from under + value (v.). Sense of “to estimate or esteem too low” is recorded from 1610s. Meaning “to rate at too low a monetary value” is attested from 1620s.