Concerns over the impact of a tightening job market on the prospects for inflation and rising bond yields sent the major domestic equity indexes well into negative territory on Friday, with the Dow Jones Industrials Average down about 666 points, for its largest daily percentage loss in 20 months.

As a result, the three major equity indexes chalked up their largest weekly losses in two years, after closing at record highs the previous week. The S&P 500 and Dow saw their worst weeks since early January 2016 while Nasdaq had its worst week since early Feb 2016.

Overnight stock price losses accelerated after the Labor Department reported employment grew more than expected in January with the largest wage gain in more than 8-1/2 years. The picture of workers commanding higher salaries fueled expectations that inflation is on the rise, which could prompt the Federal Reserve to take a more aggressive approach to rate hikes this year.

That caused the 10-year Treasury yield to surge to 2.8450 percent, the highest level for that statistic since Jan. 2014, which could make returns on Treasuries look more attractive relative to stocks.

However, many on the Street are not convinced that the bull market in stocks that that saw the S&P 500 rise 5.6 percent in January is over. In fact, many say a pullback was overdue.

S&P 500 e-mini stock futures EScv1 extended losses in the cash market. S&P 500 futures moved 2.3 percent lower, making it the largest daily percentage drop since September 2016.

Although all 11 major sectors of the S&P 500 ended the trading day on Friday, down, technology weighed the heaviest, with Microsoft pulling the sector down 3.0 percent.

The CBOE Volatility Index rose more than four points to 17.86, its highest since November 2016. Trading volume in VIX options hit a record high.

Meanwhile, look for fourth-quarter earnings growth of 13.6 percent for the S&P 500, up from 12 percent on January 1. Half of the index’s companies have reported, 78 percent of which beat Street expectations, according to Thomson Reuters data.

Exxon Mobil and Chevron Corp were down 5.1 percent and 5.6 percent, respectively, after the oil companies posted lower-than-expected fourth-quarter earnings.

Alphabet fell 5.3 percent after the Google parent’s fourth-quarter profit came in below consensus on increased spending.

Apple was off by 4.3 percent as investors due to concerns over the iPhone maker’s weak outlook amid reports of scaled back iPhone X production.

Amazon was a bright spot, up 2.9 percent as the Street’s analysts quickly upped their price targets following the online retailer’s impressive earnings report.

Approximately 5.39 billion shares changed hands on the major domestic equity exchanges, as compared to the 7.33 billion share average over the past 20 trading days.

Jobs Numbers Rise

Nonfarm payrolls rose by 200,000 jobs last month after rising 160,000 in December, the Labor Department said on Friday. Wages were also higher with both numbers recording their largest annual gain in more than 8-1/2 years. The numbers also reinforced expectations that inflation will push higher this year as the labor market hits full employment.

The unemployment rate was unchanged at a 17-year low of 4.1 percent. Average hourly earnings rose 0.3 percent in January to $26.74, building on December’s solid 0.4 percent gain.

That raised the year-on-year increase in average hourly earnings to 2.9 percent, the largest increase since June 2009, up from 2.7 percent in December. Workers, however, put in fewer hours last month. The average workweek fell to 34.3 hours, the shortest in four months, from 34.5 hours in December.

The employment report underscored the strong momentum in the economy, raising the possibility that the Federal Reserve could be a bit more aggressive in raising interest rates this year. The Fed has forecast three rate increases this year after raising borrowing costs three times in 2017.

Fed officials on Wednesday expressed optimism that inflation will rise toward its target this year. Policymakers, who voted to keep interest rates unchanged, described the labor market as having “continued to strengthen,” and economic activity as “rising at a solid rate.” The financial markets expect a rate hike in March.

Economists say job gains are being driven by buoyant domestic and global demand. Given that the labor market is almost at full employment, economists saw little to push up job growth from the Trump administration’s $1.5 billion tax cut package passed by the Republican-controlled Congress in December, in the largest overhaul of the tax code in 30 years.

Republicans have promoted the fiscal stimulus, which includes a reduction in the corporate income tax rate to 21 percent from 35 percent, as creating jobs and increasing economic growth.

According to outplacement consultancy firm Challenger, Gray & Christmas, only seven companies, including Apple, had announced plans to add roughly a combined 37,000 new jobs in response to the tax cuts as of the end of January.

The expectation is for nonfarm payrolls rising by 180,000 jobs last month and the unemployment rate unchanged at 4.1 percent. January’s jobs gains were above the monthly average of 192,000 over the past three months. The economy needs to create 75,000 to 100,000 jobs per month to keep up with growth in the working-age population.

Job growth is expected to slow this year as the labor market hits full employment. Companies are increasingly reporting difficulties finding qualified workers, which economists say will force some to significantly raise wages as they compete for scarce labor.

Wage growth last month was likely supported by increases in the minimum wage which came into effect in 18 states in January. It was also likely helped by the tax cut. Companies like Starbucks and FedEx have said they will use some of the savings from lower taxes to boost wages for workers.

Further gains are expected in February when Walmart raises entry-level wages for hourly employees at its U.S. stores. Annual wage growth is now close to the 3 percent that economists say is needed to push inflation towards the Fed’s 2 percent target.

The January household survey data incorporated new population controls. The department also released annual revisions to the payrolls data from the survey of employers and introduced new factors to adjust for seasonal fluctuations.

It said the level of employment in March of last year was 146,000 higher than it had reported, on a seasonally adjusted basis. The unemployment rate dropped seven-tenths of a percentage point in 2017 and economists expect it to hit 3.5 percent by the end of the year.

Employment gains were widespread in January. Manufacturing payrolls increased by 15,000 last month after rising 21,000 in December. The sector is being supported by strong domestic and international demand. A weak dollar is also providing a boost to manufacturing by making U.S.-made goods more competitive on the international market.

Hiring at construction sites picked up last month despite unseasonably cold weather. Construction payrolls increased by 36,000 jobs after rising 33,000 in December. Retail employment rebounded by 15,400 jobs in January after slumping 25,600 the prior month.

Government employment increased by 4,000 jobs following two straight months of declines. There were also increases in payrolls for professional and business services, leisure and hospitality as well as healthcare and social assistance.