March 15 (Reuters) - Investors will scrutinize demand for $24 billion of 20-year Treasury debt this week after the recent selloff in U.S. government bonds fed worries about how high yields can climb without destabilizing the stock market. While Tuesday’s 20-year bond auction is expected to see relatively strong investor interest, a weak auction could send yields still higher. That in turn could weigh on technology stocks that rely on cheap funding for growth. “There’s good end-user demand but every auction will be looked into a little bit more these days,” said Justin Lederer, an interest rate strategist at Cantor Fitzgerald in New York. “It still feels like this market hasn’t really found a bottom yet in price.” The benchmark 10-year Treasury note yield reached 1.642% on Friday, its highest since February 2020 as the market eyed prospects of increased debt supply to fund the $1.9 trillion coronavirus relief plan, and signs of an improving economy in the wake of a vaccine roll out. The yield on the 20-year bond rose to 2.319%, the highest since that maturity was relaunched by the U.S. Treasury in May 2020. Auctions last week for 10-year notes and 30-year bonds “weren’t bad” after offerings in February for seven-year notes and 20-year bonds were met with weak demand, according to Lou Brien, market strategist at DRW Trading in Chicago. “We still don’t have inflation but we are starting to generate a little more inflation expectations and so that makes some of the auctions a little more difficult,” he said. As for Thursday’s auction of $13 billion of 10-year Treasury Inflation-Protected Securities (TIPS), Brien said it should go well if inflation expectations are up. The offering comes a day after the Federal Reserve releases its March meeting statement and Chair Jerome Powell is grilled by the media for clues on policy moves. “I think Powell will reiterate the stance ... that he is not concerned with the potential for inflation this year or a large burst of it,” Brien said. “If he does and the market listens to him, (the TIPS auction) may, all else being equal, not go as well.” The 30-year TIPS yield rose over the 0% threshold for the first time since June a day after a weak auction of the security on Feb. 18. The 10-year TIPS yield traded as high as -0.619% on Friday. (Reporting By Karen Pierog in Chicago and Karen Brettell in New York; Editing by Alden Bentley and David Gregorio)