Investor demand for U.S. short-term debt remained firm at the start of the week as the Treasury sold $87 billion of three-month bills at a high rate of 4.165%, drawing a bid-to-cover ratio of 3.17. The department also placed $77 billion of six-month bills at 3.980%, with a 3.14 bid-to-cover. Both auctions cleared without signs of strain, suggesting robust appetite for front-end securities even as the federal deficit widens. Building on that momentum, the Treasury said it will auction a record $100 billion of four-week bills on Aug. 7, settling Aug. 12. The size tops the previous $95 billion offering and underscores the government’s escalating near-term funding needs. The larger sale comes as officials lean on short-dated issues, viewed by investors as a haven from the higher yields demanded on longer maturities.