FOREX-Yen and Swiss franc jump, dollar drops as DeepSeek concerns drain risk appetite

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U.S. dollar index falls

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Yen and Swiss franc jump as investors seek safety

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Tech selloff pushes U.S. stocks lower

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Central bank policy meetings and economic data in focus

(Updates headline, first graph and prices throughout, adds fresh analyst quote)

By Chibuike Oguh and Stefano Rebaudo

NEW YORK, Jan 27 (Reuters) - The Japanese yen and the Swiss franc gained against major currencies on Monday amid a selloff in technology stocks as markets weighed the implications of a Chinese startup launching a free open-source artificial intelligence model.

China's DeepSeek rolled out a free AI assistant that it says uses lower-cost chips and less data, seemingly challenging a widespread bet in markets that AI will drive demand along a supply chain from chipmakers to data centres.

The yen and Swiss franc strengthened, while the yield on the benchmark 10-year Treasury note dropped 6 basis points to a one-month low of 4.561% as investors rushed into safe-haven assets and government bonds.

The benchmark S&P 500 was down 1.6% to 6,003.04, dragged down by technology stocks. AI chipmaker Nvidia (NVDA) was down nearly 14% to $123.02.

"U.S. equity markets are selling off hard and foreigners were large record buyers of U.S. stocks in December. That is a contrarian indicator," said Marc Chandler, chief market strategist at Bannockburn Global Forex in New York.

"Many people were concerned already that U.S. stocks were overvalued. DeepSeek exposes these concerns. And what it did was the U.S. 10-year yield is down. That is why the yen and the Swiss franc have done relatively well."

The Japanese yen rose 0.95% to 154.56 against the dollar after tightening up to 153.71, its strongest since mid-December. The Swiss franc rose 0.57% against the greenback to $0.90105.

The dollar index, which measures the greenback against a basket of currencies including the yen and the euro, fell 0.34% to 107.30, after dropping to its lowest since mid-December. The euro was up 0.09% at $1.0502.

The dollar recorded its biggest weekly loss in more than a year last week on expectations that tariffs enacted by U.S. President Donald Trump will be lower than previously feared. But concerns have resurfaced as the U.S. and Colombia pulled back from the brink of a trade war.

The Mexican peso, a barometer of tariff worries, weakened 1.6% to 20.609 per dollar. The Canadian dollar was down 0.33% versus the greenback at 1.44 per dollar. Trump said last week he may impose duties on products from Canada and Mexico from Feb. 1.

"The Mexican peso is the weakest of the emerging market currencies today. I think it suffered in sympathy with Colombia and the threat of tariffs," Chandler said.

"While the Canadian dollar is down, it is doing a little bit better than the other dollar block currencies like the Aussie and kiwi."

The Australian dollar dropped 0.48% versus the greenback to $0.6277. The kiwi weakened 0.53% versus the greenback to $0.5679.

Major central banks, including the Federal Reserve and the European Central Bank, will meet this week after the Bank of Japan raised its rates and Governor Kazuo Ueda said last week the BoJ would keep tightening its policy as wage and price increases broaden.

The personal consumption expenditures (PCE) price index - the Fed's favourite inflation gauge - is due on Friday, while inflation data will be released from Germany, France and Japan on Friday as well.

"I think the market's going to turn cautious now ahead of Wednesday when both the Federal Reserve and the Bank of Canada meet," Chandler added.

Bitcoin fell 3.33% to $101,601.14, but still traded near the record high of $109,071.86 touched last week. Ethereum declined 5.78% to $3,136.05.

(Reporting by Stefano Rebaudo and Chibuike Oguh in New York. Editing by Mark Potter, Sharon Singleton and Hugh Lawson)