The Dow Jones Industrial Average dropped by 558 points on Friday, capping a wild week of trading that saw the blue-chip index lose close to 5 percent of its value. It was the worst week for the Dow since March, and erased all gains for the year.

The Dow started the day with a spike of 150 points after the Department of Labor released a generally tepid jobs report, only to plummet by mid-afternoon to a session low of 662 points down as markets continued to absorb the destabilizing impact of President Donald Trump's protectionist trade policies.

The broader S&P 500 lost 2.3 percent of its value, and a tech sell-off fueled a drop of 3 percent on the Nasdaq composite index. Tech giants Alphabet and Apple both lost all of their gains for the year. Apple's share price has been steadily falling after a litany of analysts cut their price targets for the smartphone maker amid concern over waning demand for the iPhone.

The market also hiccuped after St. Louis Federal Reserve President James Bullard suggested the central bank should not introduce a rate hike in December — the first to publicly make such a pronouncement. Bullard cited the inverted yield curve, a phenomenon that many see as indicative of an impending recession.

Even a production cut agreement by OPEC and an ensuing spike in oil prices failed to buoy markets. The oil cartel concluded its two-day meeting Friday with a deal — including non-member Russia — to curb output by a total of 1.2 million barrels per day in order to stabilize the price of crude, which has fallen 30 percent in the last two months.