Investors largely shrugged off a downgrade of the U.S.' credit rating in Monday trading, as stocks ended the day mostly flat.

The Dow Jones Industrial Average added more than 130 points for an increase of 0.32%. The broader S&P closed up 0.09% and the tech-heavy Nasdaq gained 0.02%.

Late Friday, Moody’s became the third and final major ratings agency to downgrade U.S. debt, reducing it by one notch from AAA to Aa1 . Credit ratings agencies help determine how reliably a country can pay off its debt.

Yet the market for U.S. government debt has so far remained mostly stable. As of 4 p.m., the yield on the 10-year Treasury note — the government’s benchmark loan asset — was only a few percentage points above where it traded Friday, climbing to 4.46%. That remans well below the most recent high of 4.59% briefly seen last month.

“The downgrade itself doesn’t seem so far to have made much of a market splash,” analysts at the Capital Economics research consultancy wrote in a note.

While the government’s debt yield — or the percentage return demanded by investors for lending to it — briefly climbed Monday, the analysts said, “the moves haven’t been enormous.” They noted similar market reactions to the prior U.S. credit downgrades, which occurred in 2011 and 2023.

While stock and bond buyers went largely unscathed Monday, home buyers now face higher mortgage costs as a result of the downgrade. The average rate on the popular 30-year fixed-rate loan hit as much as 7.04% on Monday, according to Mortgage News Daily. That was the highest level since April 11.

“The average mortgage lender had to account not only for the market movement in Friday’s closing minutes, but also to the additional weakness seen this morning. That makes for a fairly big jump, day-over-day, but it does very little to change the bigger picture,” Matthew Graham, chief operating officer at Mortgage News Daily, said according to CNBC .

In remarks accompanying its downgrade, Moody’s said America’s ability to control its balance sheet has eroded over the years, something that has forced yields higher.

“Successive U.S. administrations and Congress have failed to agree on measures to reverse the trend of large annual fiscal deficits and growing interest costs,” it said. “We do not believe that material multi-year reductions in mandatory spending and deficits will result from current fiscal proposals under consideration.”

But while Friday's downgrade garnered international headlines, individual stock buyers continue to prop up the market, helping to counterbalance the declines.