U.S. stocks climbed Monday to claw back some of the losses from their worst week in nearly a year and a half.

The S&P 500 rallied 1.2%, though it didn’t recoup all of its drop from Friday, let alone from the rest of the four-day losing streak that it broke. The Dow Jones industrial average rose 484 points, or 1.2%, and the Nasdaq composite gained 1.2%.

Boeing climbed 3.4% after reaching a tentative deal with its largest union on a new contract that, if ratified, will avoid a strike that threatened to shut down aircraft production by the end of the week.

Nvidia and other Big Tech companies also returned to their long-held position of leading the market, at least briefly. Nvidia climbed 3.5% and was the strongest force pushing the S&P 500 upward.

After likewise climbing a bit in the morning, Treasury yields later pared their gains. That followed sharp swings in the bond market last week, when a highly anticipated update on the U.S. job market came in weak enough to worsen worries about the slowing U.S. economy.

On Wall Street, Palantir Technologies jumped 14.1% in its first trading after S&P Dow Jones Indices said it would add the company to its S&P 500 index. Dell Technologies rose 3.8% after likewise getting a notice of promotion to the index.

Apple’s stock was virutally flat after the company unveiled its latest iPhone model, the 16. It’s the first model to be tailored specifically for artificial intelligence, with expected improvements to its often dim-witted virtual assistant, Siri.

Trading in Big Lots was halted after the discount retailer filed for Chapter 11 bankruptcy protection and said it plans to sell its assets and ongoing business operations to private equity firm Nexus Capital Management.

All told, the S&P 500 rose 62.63 points to 5,471.05. The Dow gained 484.18 to 40,829.59, and the Nasdaq composite gained 193.77 to 16,884.60.

In the bond market, the 10-year Treasury yield edged down to 3.71% from 3.72% late Friday.

— Associated Press