NEW YORK (Reuters) -U.S. stocks ended higher on Monday, with Apple giving the S&P 500 its biggest boost as the White House exempted smartphones and computers from new tariffs. 

Uncertainty over future tariffs kept a lid on optimism, with the main indexes finishing off their highs of the day. Investors remain worried about how companies will manage supply chains as more changes are expected on the tariff front.

The United States unveiled the exemptions on Friday, but President Donald Trump said on Sunday that he would be announcing the tariff rate on imported semiconductors over the next week.

Global technology shares mostly rose on the news, especially for companies that rely on imports from China. Shares of iPhone maker Apple rose 2.2%. Dell Technologies gained 4% and HP climbed 2.5%.

At the same time, an index of semiconductors rose just 0.3% and shares of top chipmaker Nvidia were down 0.2% on the day.

Monday's trading was choppy, as has been the case since Trump announced sweeping tariffs on April 2. Investors, worried that a global trade war will push the economy into recession, have seen some of the biggest swings in the market in years as the Trump tariff news changes.

"Really what we have is just continued uncertainty and inability for consumers and businesses and investors to plan much going forward or have reason to commit to long-term spending plans," said Jed Ellerbroek, a portfolio manager at Argent Capital Advisors in St. Louis, Missouri.

The Dow Jones Industrial Average rose 312.08 points, or 0.78%, to 40,524.79, the S&P 500 rose 42.61 points, or 0.79%, to 5,405.97 and the Nasdaq Composite rose 107.03 points, or 0.64%, to 16,831.48.

The CBOE Volatility Index, Wall Street's "fear gauge," eased to 30.89, its lowest closing level since April 3.

Technical analysts noted, though, that the S&P 500 is now in a "death cross" pattern, which marks a spot where a shorter-term correction could turn into a longer-term downtrend.

A death cross occurs when the 50-day moving average slips below the 200-day moving average.

History suggests the ominous-sounding signal may not necessarily mean equities face more significant downside. The S&P 500 remains down about 8% for the year so far.

Markets will be closed on Good Friday, but this week is still expected to bring some key results from U.S. companies.

U.S. companies have begun to report results for the 2025 first quarter and, with tariff troubles looming, corporate executives may hold back on giving much guidance.

"Everybody knows the future is going to look a fair amount different than the past, and management teams are going to be really hesitant to commit to much," Ellerbroek said.

Still, shares of Goldman Sachs rose 1.9% on Monday after the bank reported higher first-quarter profit. Quarterly results from companies including Netflix and UnitedHealth Group are also on the radar this week.

Also gaining were some drugmakers after Pfizer said it would end the development of its experimental weight-loss pill. Pfizer shares ended 1% higher.

On the Nasdaq, 3,266 stocks rose and 1,200 fell as advancing issues outnumbered decliners by about a 2.72-to-1 ratio. There were 43 new highs and 101 new lows.

On the NYSE, advancing issues outnumbered declining ones by a 4.4-to-1 ratio . There were 45 new highs and 65 new lows.

Volume on U.S. exchanges was 18.2 billion shares, compared with the roughly 18.7 billion average for the full session over the last 20 trading days.

(Reporting by Caroline Valetkevitch in New York; Additional reporting by Lisa Mattackal and Purvi Agarwal in Bengaluru; Editing by Shinjini Ganguli, Pooja Desai and Matthew Lewis)