Dow slides 200 points on concerns of retail investors' speculative trading

• US equities slid on Friday as investors braced for more day-trader-fueled volatility and balked at Johnson & Johnson's COVID-19 vaccine data.
• Reddit traders drove GameStop, AMC, and others higher after brokers removed some trading restrictions.
• Johnson & Johnson said its vaccine was 66% effective, but data suggests the shot is less beneficial against the virus strain first identified in South Africa.
• $4.

US stocks fell on Friday as investors shunned retail traders' speculative bets and disappointing vaccine data from Johnson & Johnson.

$4, $4, and other Reddit-favorite stocks rebounded as day traders piled back into their risky positions. The highly volatile names have taken center stage in the market, and moves from Robinhood, Interactive Brokers, and other platforms to restrict trading have been met with calls for congressional hearings and reform.

Market participants fear that the retail traders' targeting of shorts could force hedge funds to cover their bearish bets by selling their long positions. While the phenomenon has rocked only some funds, strategists have raised concerns about a growing market disruption.

Here's where US indexes stood soon after the 9:30 a.m. ET open on Friday:

• $4: 3,764.60, down 0.60%
• $4: 30,397.10, down 0.67% (206.26 points)
• $4: 13,297.82, down 0.31%

Read more: $4

"It was already becoming apparent that stock markets had lost their buzz," said Craig Erlam, a senior market analyst at Oanda. "Suddenly the talk switched to whether we're seeing frothy markets, bubble-like behavior and the pullback was underway."

Johnson & Johnson announced on Friday that $4, well below the efficacy demonstrated by other companies' two-dose programs. Johnson & Johnson said its vaccine was also less effective in South Africa, suggesting the shot is less beneficial at protecting against the more contagious virus strain first identified in that country.

Stocks soared to record highs throughout January on the hopes that vaccine rollouts and stimulus from the Biden administration could accelerate the US economic rebound. Johnson & Johnson's announcement underscores the difficulty in ending the pandemic and reaching herd immunity.

Johnson & Johnson sank on the news.

Read more: $4

$4 for the first time since January 15 after Tesla CEO Elon Musk added "#bitcoin" to his Twitter bio. The most popular cryptocurrency hovered at about $32,000 for about a week after soaring to record highs at the start of the new year.

Spot gold climbed as much as 1.6%, to $1,874.08 per ounce. The US dollar weakened slightly against a basket of Group-of-20 currency peers, and Treasury yields edged higher.

Oil prices gained. $4 rose as much as 1.1%, to $52.92 per barrel. $4, oil's international benchmark, fell 1.1%, to $56.15 per barrel.

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