US Treasuries fell during New York trading on Monday, with the yield curve steepening as a busy slate of corporate bond issuance pressured the market. Investment-grade bond sales in the US hit a record for the same month for the third consecutive period, with 12 issuers raising a combined $9.1 billion on the day.

Meanwhile, stalled US-Iran negotiations and renewed Middle East tensions pushed oil prices higher, adding further downward pressure on Treasuries. Just after 3 p.m. in New York, Treasury yields rose 1 to 5 basis points across the curve in a bear steepening move, with the 2s10s spread widening 2.5 basis points on the day and the 5s30s spread expanding nearly 4 basis points. The 10-year yield hovered near its intraday high, up about 3 basis points from Friday's close.

Corporate issuance was led by a $2 billion three-part bond sale from Bank of New York Mellon. August investment-grade issuance has now surpassed $145 billion, marking the highest on record for the month and exceeding July's $139.6 billion record for that period. WTI crude futures pulled back from session highs late in the day but still traded roughly 2.4% higher, keeping upward pressure on Treasury yields.

On the news front, US Energy Secretary Wright indicated the US is taking a long-term view regarding Iran. SOFR options saw light volume but retained a bias toward upside protection, with traders betting that the amount of rate hikes priced into the short end of the curve is excessive. As of 4:12 p.m. Eastern Time, the 2-year yield rose 1.3 basis points to 4.1816%, the 5-year gained 1.6 basis points to 4.3798%, the 10-year climbed 3.6 basis points to 4.7279%, and the 30-year advanced 5.6 basis points to 5.3157%. The 5s30s spread widened about 4.2 basis points to 93.51 basis points, while the 2s10s spread increased roughly 2.7 basis points to 54.42 basis points.