Stock Market Today: Dow Plunges 643 Points as Treasury Yields Climb Stocks sold off sharply Monday as the 10-year Treasury yield continued to climb. The yield on this closely watched government bond jumped 4 basis points to 3.029% – marking its first trip above the 3% threshold since late July. (A basis point is one-one hundredth of a percentage point.) SEE MORE 10 Best Bond ETFs to Buy Now Uncertainty over the Federal Reserve''s rate-hike timeline – specifically, the "how long?" and "by how much?" narratives – is spooking investors, with commentary last week from central bank officials hinting at the potential for a third straight 75 basis-point increase at the September meeting. "Naturally, all eyes are on Jackson Hole later in the week and in particular, the appearance of Fed Chair Jerome Powell," says Craig Erlam, senior market strategist at currency data provider OANDA. Powell is scheduled to deliver a speech at the central bank''s annual symposium in Wyoming on Friday morning. "This platform has in the past been used to make significant announcements and so every year, traders are left on the edge of their seats in case of another this time around." Sign up for Kiplinger''s FREE Investing Weekly e-letter for stock, ETF and mutual fund recommendations, and other investing advice.