* Machinery, auto stocks tumble after weak orders data
* Shin-Etsu jumps on share buyback plan
* Financials underperform on weak U.S. inflation
By Ayai Tomisawa
TOKYO, March 13 (Reuters) - Japan's Nikkei ended lower on Wednesday as weak machinery orders dragged down shares of machinery makers and exporters, and investors worried about Britain's exit from the European Union took profits.
Financial stocks, which benefit from higher yields, also underperformed as U.S. yields tumbled under pressure from weak inflation data, supporting expectations that the U.S. Federal Reserve will hold interest rates steady this year.
The Nikkei share average ended 1.0 percent lower to 21,290.24 points, after surging 1.8 percent the previous day.
Japanese machinery orders fell in January at the fastest pace in four months as the U.S.-China tariff war hit global trade and dented demand from the country's auto and telecommunications equipment sectors.
Among chip equipment makers, Advantest Corp shed 2.3 percent, while Tokyo Electron lost 1.3 percent. TDK Corp fell 3.5 percent and Hitachi Ltd dropped 2.9 percent.
"A bad machinery figure was somewhat expected," said Yoshinori Shigemi, global market strategist at JPMorgan Asset Management.
The U.S.-China trade war, which has dragged down Japan's corporate earnings and demand, will likely continue to pressure machinery and cyclical stocks, he added.
"Due to falling demand in autos and chips, it's difficult to buy stocks related to these sectors," Shigemi said.
Among automakers, Mazda Motor and Subaru Corp both dropped 1.4 percent.
Insurers also contributed to the weaker market, with Dai-ichi Life Holdings off 1.5 percent, T&D Holdings down 4.2 percent and MS&AD Insurance shedding 1.3 percent.
Bucking the trend, Shin-Etsu Chemical rose 2.1 percent after the company said it planned to buy back up to 3.3 percent of its own shares worth 100 billion yen.
The broader Topix skidded 0.8 percent to 1,592.07. (Reporting by Ayai Tomisawa; editing by Darren Schuettler)