The Nasdaq tumbled 1.6% on Monday, confirming a correction as it was dragged down by Alphabet, Facebook and Amazon on fears the companies are the targets of t antitrust regulators. A correction is defined as a 10 percent drop from the most recent 52-week high.

While the sell-off in the internet heavyweights was the largest drag on the Nasdaq, the index has been falling steadily since its May 3 record closing high as investors worried about slowing global growth and the escalating U.S.-China trade war.

The S&P 500 had a volatile session and ended the day down 0.3 percent, while the Dow Jones Industrial Average ended the session virtually unchanged.

The benchmark S&P 500 swung in and out of negative territory during the day as comments swirled around trade battles with both China and Mexico, as well as Trump’s decision on Friday to end preferential trade treatment for India.

In other business news, an ISM survey showed manufacturing growth unexpectedly slowed in May, driving demand for the safety of government bonds. Two-year yields hit their lowest since September 2017 on growing conviction that the Federal Reserve will start cutting interest rates to stave off a recession.

High-profile internet stocks dominated trading, with Facebook down 7.5% after the Wall Street Journal reported that the Federal Trade Commission has secured the right to examine how the social media company’s practices affect digital competition. The stock was on pace for its biggest one-day drop since July 26.

Alphabet fell 6% on rumors that the Justice Department is preparing an investigation to determine if the Google parent broke antitrust laws. Amazon.com fell 4.6% on a report that the e-commerce giant could be put under the watch of the FTC.

The communication services sector, which includes Google and Facebook, was down 2.8%, the largest fall of the S&P’s 11 major sectors, while Amazon shares helped pull the consumer discretionary sector down 1.2%.

The S&P materials sector was the greatest percentage gainer of the S&P’s major sectors, with a 3.4% advance. Dupont’s 11.5% gain accounted for roughly half of the sector’s rise in the first trading session after it spun off its Corteva Inc agriculture business.

Healthcare was one bright spot for the Nasdaq, with the Nasdaq biotech index climbing 1.2%, helped by shares of companies including Amgen and Gilead. Amgen and Merck reported positive drug data at the annual American Society of Clinical Oncology meeting in Chicago.

Amgen rose 3.4% after its drug showed a high response rate in a small lung and colon cancer trial, while Merck gained 1.3% after data indicated nearly a quarter of patients who received immunotherapy Keytruda as an initial treatment for advanced lung cancer were still alive after five years.

Approximately 8.34 billion shares changed hands on the major domestic equity exchanges, as compared to the 7.11 billion share average for the past 20 sessions.

Factory Activity Slows

Manufacturing growth slowed in May to its weakest pace in over two years concerns over the ongoing trade war between the United States and China has taken a toll.

According to the Institute for Supply Management its Manufacturing Purchasing Managers Index declined to 52.1 from 52.8 in April, hitting the lowest level since October 2016. Nonetheless, a reading above 50 indicates growth. 

A separate survey on purchasing manager sentiment by IHS Markit also pointed to a slowdown in factory activity during May.

The reports suggest that risks to the economy are rising due to a slowing global economy and Trump’s efforts to overhaul America’s relationship with its major trading partners.

The White House has ordered sharp tariff increases on a host of Chinese imports in 2018 and this year, while on Friday he threatened to hike tariffs on all Mexican imports unless Mexico stems the flow of unauthorized immigrants into the United States. Many U.S. factories depend on Mexican suppliers for goods assembled in America.

U.S. trading partners including China and Mexico have retaliated against Trump’s tariffs with higher taxes on U.S. exports. This is also putting pressure on U.S. factories.

ISM’s factory employment index ticked higher to 53.7 after April’s reading of 52.4. The index has fallen by 11% since October 2017.

Look for rising tariffs to hit corporate profits and lead to higher consumer prices.

The ISM survey was taken before Trump threatened new tariffs on Mexico starting next month. The threat prompted a broad outcry from U.S. businesses.

Global trade tensions ratcheted higher throughout May after Trump ordered tariffs on billions of dollars of imported goods from China to rise to 25% from 10%, and progress toward a trade deal between the world’s two largest economies ground to a halt.

“Respondents expressed concern with the escalation in the U.S.-China trade standoff,” said Timothy Fiore, who chairs the ISM’s Manufacturing Business Survey Committee.

Factories reported the weakest output growth last month since August 2016 with a production index reading of 51.3, down from 52.3 in April. New orders recovered modestly, but the backlog of orders contracted for the first time since January 2017.

The Commerce Department also indicated that construction spending, which has suffered from a slowdown in the housing market, was flat in April. A fall in spending on private residential projects was balanced with a rise in public construction outlays.