Summarize this content to 2000 words in 6 paragraphs The U.S. stock market is headed for one of its worst weeks in many months, after a series of dizzying policy shifts on tariffs from the White House.The S&P 500 nudged higher at the start of trading on Friday. The muted move still leaves the index 3.4 percent lower for the week, on course for its third consecutive week of losses and its worst week since September.There has been a sharp mood shift since the index hit a record high less than a month ago, as investors have become worried about the trajectory for economic growth, made worse by tariffs on imports from the country’s largest trading partners. Surveys have also showed mounting concern among consumers.On Friday, a fresh report on the labor market offered some relief. The data showed a pace of hiring moderate enough to temper fears about resurgent inflation, yet robust enough to avoid worries about a slowing economy.Lara Castleton, U.S. head of portfolio construction and strategy at Janus Henderson Investors, said the data would probably ease “overly sour expectations” about the economy.“After confidence on the economy has taken a turn,” she said, “market participants were looking to either confirm or reverse that sentiment.”Investors who had hoped that President Trump’s tariff threats were just a negotiating tactic were disappointed on Tuesday when 25 percent tariffs came into force on Mexico and Canada, and an additional 10 percent tariffs on China. Concessions were made on Thursday, suspending the tariffs on many goods from Canada and Mexico, but it failed to stoke a rally.“I think the markets are essentially taking President Trump a bit more seriously on tariffs,” said Jim Caron, chief investment officer of the portfolio solutions group at the Morgan Stanley Investment Institute. He said that despite the recent sell-off, major stock indexes remained close to record highs and the economy remained in good shape.Much of the sell-off has been driven by big technology companies, which, because of their size, have a big effect on broad indexes. Since the S&P 500 peaked on Feb. 19, the index has fallen 6.5 percent. A separate measure that gives all of the stocks an equal weight in the index has fallen just 4.1 percent over the same period.What isn’t clear is whether investors are selling because they see the tide turning for tech companies or because of broader concerns.“In the last couple of weeks, and maybe for the next couple of weeks, we have gone through a very challenging news cycle,” Mr. Caron said. “We need to get through that and assess how much damage there is to markets.”
