(Updates to midafternoon)

TOKYO, Jan 30 (Reuters) - Japanese stocks slipped on Wednesday as Asian stock markets weakened and investors worried about the performance of Wall Street shares after the Federal Reserve's decision on interest rates later in the day. The market is also waiting for earnings from a slew of major companies this week, including Canon Inc (7751.T: Quote, Profile, Research) later on Wednesday.

The Federal Reserve is widely expected to cut interest rates by 50 basis points after its sharp emergency rate cut last week, an effort to stave off a U.S. recession.

"If the Fed acts as the market expects, this means there will be few major factors remaining for the market to trade on, and investors here in Japan are worried that Wall Street could fall as a result," said Tsuyoshi Segawa, an equity strategist with Shinko Securities.

"Investors are also drawing back ahead of Thursday, which marks the peak of earnings announcements this time around, with many of them wanting to wait and see."

At 0437 GMT the benchmark Nikkei .N225 was down 0.9 percent at 13,356.47, a loss of 122.39 points. The broader TOPIX .TOPX was down 0.5 percent at 1,321.81.

Negative sentiment in other Asian share markets also pressured Tokyo stocks. The MCSI index of Asian stocks outside Japan was down 1.4 percent.

Shin-Etsu Chemical (4063.T: Quote, Profile, Research) and chip-related peers such as Sumco Corp (3436.T: Quote, Profile, Research) tumbled after Sumco said on Tuesday that it would expand a plant in western Japan and raise capacity, prompting JP Morgan to cut Sumco's price target.

"Concern about wafer shortages is not an issue at present. If anything, oversupply looks to be emerging," wrote Nobuhito Owaki.