Wall Street ended lower after a choppy session on Monday, with declines in Exxon Mobil and other energy companies weighing against gains in Boeing as investors digested the US stock market's biggest monthly gains in two years.

Stocks gave up some of a strong rally from last week that was driven by bets the Federal Reserve may not need to be as aggressive with interest rate hikes as some had feared.

Also helped by stronger-than-expected second-quarter results, the S&P 500 and the Nasdaq in July posted their biggest monthly percentage gains since 2020.

The S&P 500 bounced between gains and declines on Monday as some investors became more cautious in the wake of that recent rally.

The Federal Reserve says it aims to tame inflation and cool down demand with the interest rate hikes, but some investors and analysts worry that its aggressive moves could drive up unemployment and cripple the economy.

"There are still a lot of questions about whether we are really out of the woods economically, and we probably aren't," said Tom Martin, senior portfolio manager at GLOBALT Investments in Atlanta. "We're not even close on the (economic) effects of the Fed raising interest rates."

US manufacturing activity slowed-less-than-expected in July, with signs that supply constraints are easing, a report showed.

That data came on the heels of surveys indicating factories across Asia and Europe struggled for momentum in July as flagging global demand and China's Covid-19 curbs slowed production.

Oil prices fell on demand concerns, which in turn weighed on the energy sector. Exxon Mobil slid 2.5 percent and was among the stocks contributing the most to the S&P 500's decline.

Boeing Co gained 6.1 percent after Reuters reported the US aviation regulator approved the planemaker's inspection and modification plan to resume deliveries of 787 Dreamliners.

The S&P 500 declined 0.28 percent to end the session at 4,119 points. The Nasdaq declined 0.18 percent to 12,369 points, while Dow Jones Industrial Average declined 0.14 percent to 32,799 points. (Reuters)