US technology stocks tanked Monday and fueled a big risk-off move lower after China's DeepSeek unveiled its new AI model, as the new competitor appeared to cast doubt on the sky-high valuations of Nvidia and other US AI champions. The Dow Jones industrial average managed to rise 0.7 percent, the S&P 500 fell 1.5 percent and the Nasdaq plunged 3.0 percent. US bond yields dropped in a flight to quality, the dollar was mostly higher, and oil prices declined.

A flight from risk spurred a big shift into US Treasuries and safe-haven currencies like the yen and Swiss franc. Investors appeared spooked by the advent of DeepSeek, which appears to be far more economical than its US competitors, which have accounted for a huge share of the market's advance and much of the bull case for US stocks. Caution before the Federal Reserve policy announcement, big earnings reports, and key economic data this week added to the risk aversion.

Growth stocks fared worst while value fared better. Among sectors, technology suffered the most, along with industrials, energy, utilities and communications services. Holding up best were health care, consumer staples, financials and real estate.

Market Reflections track market reaction to the trading day's major events. Economic data, policymaker speeches, and company news are featured in this report as well as key indexes and financial instruments.

Understanding why markets respond as they do is fundamental for an investor. Market Reflections help explain how the day's events, news, and data impact the outlook for the economy and for market prices.