Canada's benchmark S&P TSX fell 20.48 points to 7,091.98.
European markets ended lower, taking a cue from U.S. equities and the Merck news. In London, the Financial Times-Stock Exchange 100 index lost 14.30 points, or 0.31%, to 4,601.30. In France, the CAC 40 was down 4.93 points, or 0.13%, to 3,858.35. And in Germany, the DAX Index was off 40.70 points, or 0.91%, to 4,442.33.
In Asia, the markets finished with losses. The Nikkei dropped 56.89 points, or 0.53%, to 10,769.20. In Hong Kong, the market was relatively flat, off 2.71 points, or 0.03%, to 10,803.45.