Whittier Trust Co . Lowers Holdings In Tetra Tech , Inc . ( Nasdaq : Ttek ) 5.0% 6.0% 7.
The Whittier Trust Co. and Canton Hathaise LLC are two of the largest shareholders of TetraTech, Inc. (NASDAQ:TTEK). The company's largest shareholders include: The Vanguard Group, Inc. BlackRock, Inc. State…