The stock VIAC, -11.59% tumbled 14.1% in morning trading. It has now plummeted 43.3% amid a four-day losing streak after the company took advantage of a recent meteoric rally to Monday’s record close of $100.34 to sell $3 billion worth of equity securities.

Don’t miss: ViacomCBS shares slide record 23% after company prices roughly $3 billion offering of equity securities.

The 41.5% selloff this week would be the stock’s worst weekly performance since it started trading in June 1990, according to FactSet data, passing the previous record 37.2% drop for the week ended Oct. 10, 2008.

In comparison, the Nasdaq Composite Index COMP, +0.31% has slipped 1.7% this week and the S&P 500 index SPX, +0.58% has ticked up 0.3%.

ViacomCBS is the parent of the Paramount+ streaming service that launched earlier this month. The stock got caught up in the momentum trade in media stocks this year, amid frenzied optimism over direct-to-consumer (DTC) streaming opportunities, even as Wall Street grew increasingly skeptical. That momentum trade led to ViacomCBS shares rocketing to a year-to-date gain of 169.3% through Monday.

Cahall noted that he let his price target ride the volatility higher, to what was a Street high $82, as he felt it was a “rare if brief” opportunity to allow momentum to rule.

“Now…times are changing and we’re changing with the times,” Cahall wrote in a note to clients.

Since the beginning of March, no less than eight of the analysts surveyed by FactSet downgraded ViacomCBS, with five analysts moving to the equivalent of sell. Of the 29 analysts surveyed by FactSet, 14 are now bearish and only four are bullish, while 11 are neutral on the stock.

Although Cahall doesn’t expect valuations to fall back to historical lows, given more DTC optimism and the potential for an “enduring non-fundamental” premium, “we do see gravity pulling the multiples closer to prior norms.”

Cahall said that while ViacomCBS’s equity offering seemed to mark “the beginning of the end” of the momentum trade, it was also a “savvy” move by the company, as it created equity value with cash on the balance sheet for more streaming investments.

He said ViacomCBS’s core business has stabilized, but it remains challenged as licensing remains “a balancing act” with content on DTC. “With the valuation still near historical highs, we expect a derating before [ViacomCBS] can be judged on fundamentals alone,” Cahall wrote.

ViacomCBS wasn’t the only media stock caught up in the momentum trade that Cahall downgraded. He also lowered his rating on AMC Networks Inc. AMCX, -6.42% to underweight from equal weight, and cut Discovery Inc.’s DISCA, -17.25% rating to equal weight.

AMC Networks shares shed 9.4% in morning trading, and has dropped 29.8% since closing at a more than five-year high of $78.63 on March 12. The stock had run up 119.8% year to date through March 12, before pulling back.

And Discovery’s stock took an 19.5% dive Friday, and has plummeted 39.8% amid a five-day losing streak since closing at a record $77.27 on March 19. Prior to the pullback, the stock had hiked up 156.8% this year through March 19.