Jan 16 (Reuters) - Canada's main stock index opened at a record high on Thursday, as the signing of an initial U.S.-China trade deal offered some relief to investors, while shares of Bombardier tumbled to a near four-year low on a profit warning.
* At 9:32 a.m. ET (1432 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE was up 30.55 points, or 0.18%, at 17,445.72.
* The trade deal, signed in Washington on Wednesday, defused an 18-month row between the two sides but still raises questions over daunting purchase commitments of U.S. goods by China, while leaving existing tariffs in place. Canadian manufacturer Bombardier Inc's BBDb.TO shares tumbled more than 35% to their lowest level since March 2016 after the company warned of lower 2019 profits and said it might have to write down significantly the value of its partnership with Airbus AIR.PA on A220 jets.