Yes, TRUSTORS is a Scrabble word!

Letter values in Scrabble US: T 1, R 1, U 1, S 1, T 1, O 1, R 1, S 1.

Is it a valid word?

TRUSTORS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

(law) a person who creates a trust by giving real or personal property in trust to a trustee for the benefit of a beneficiary; a person who gives such property is said to settle it on the trustee