TOKYO, Jan. 29 (Xinhua) -- Tokyo stocks opened lower Tuesday as investor sentiment was dented by U.S. shares dropping overnight following construction equipment behemoth Caterpillar Inc.'s quarterly earnings coming in below median market expectations.

As of 9:15 a.m., the 225-issue Nikkei Stock Average dropped 105.57 points, or 0.51 percent, from Monday to 20,543.43.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, lost 4.92 points, or 0.32 percent, to 1,550.59.

Machinery, electric appliance, and oil and coal product-linked issues comprised those that declined the most in the opening minutes after the morning bell.