PREVIEW: Tetra Tech slides; results due after the bell 

** Shares of Tetra Tech TTEK.O down about 7% on Weds, with the co seen reporting slightly lower rev in its qtrly results, due after the closing bell

** The consulting and engineering services co is expected to report qtrly rev down 1% to $1.15 bln vs $1.16 bln in the yr-ago period, and adj EPS of $0.47 vs $0.45 a yr ago, per LSEG

** Tetra Tech in September announced a $500 mln increase to its share repurchase program

** Six of nine analysts that follow the stock rate it a "buy" or "strong buy" while three rate it a "hold"

** The 12-mo median PT on the stock is $41.00; the stock was last at $37.75

** TTEK up ~13% YTD, slightly outperforming the Nasdaq's .IXIC ~10% gain