CNBC Daily Open: Treasury attempts to rein in bond yields as U.S. debt swells past $40 trillion

An electronic display shows the national debt in Washington, Aug. 19, 2026.Mandel Ngan | AFP | Getty ImagesHello, this is Hui Jie writing to you from Singapore. Welcome to another edition of CNBC's Daily Open.The U.S. Treasury Department can no longer tolerate elevated borrowing costs, and has decided to double its purchases of longer-dated bonds, depressing yields while pulling stocks higher. But with the national debt now above $40 trillion, the government may have only bought time. Inflation, the Iran war, alongside the massive debt continue to hang over the world's largest economy.What you need to know todayThe U.S. Treasury Department is looking to upscale its buyback operations for securities maturing in 10 to 30 years, "at least" doubling the amount from $2 billion to at least $4 billion per operation over the next two months.Bond prices rose following the announcement, pushing yields lower. The 30-year Treasury yield dropped roughly 9 basis points to around 5.19%, its biggest one-day decline since October 2025. The benchmark 10-year yield fell to about 4.64%.The move helped snap a three-day losing streak for stocks, with all three major U.S. indexes rising about 0.2%. Stock...