Shares of Netflix Inc. tumbled more than 8.5%, and both Etsy Inc. and Twitter Inc. set all-time lows Wednesday, as the tech sector was bludgeoned by a market selloff and Morgan Stanley downgraded the industry to underweight.

The tech-heavy Nasdaq Composite fell 160 points, or 3.4%, while the Dow Jones Industrial Average plunged 365 points, or 2.2%. The Technology Select Sector SPDR ETF, whose biggest holdings include Apple Inc. AAPL, -0.20% , Microsoft Corp. MSFT, -0.21% and Facebook Inc. FB, +1.04% , fell 2.7%.

Netflix’s NFLX, -0.08% stock plunged to $106.56, marking the stock’s worst one-day percentage decline since Oct. 15. The stock is still trading up more than 130% from 12 months ago. Shares of Etsy ETSY, +0.72% skidded 4.9% to $6.99, below the previous record low of $7.35 set on Tuesday, while Twitter’s TWTR, +1.14% tumbled 4.8% to $18.68, a dollar below the last record.

GoPro’s shares closed up 0.7% to $14.61 in the regular session, but plunged 23% in after-hours trade, on track for a record-low open of around $11.32, after the action camera maker issued a sales warning, and said it would cut 7% of its staff.

Other tech sector losers on Wednesday were Mobileye N.V. US:MBLY, Shopify Inc. SHOP, +2.91% , TripAdvisor Inc. TRIP, -1.91% and Advanced Micro Devices Inc. AMD, -0.03% , all down by more than 5%. Shares of Amazon.com Inc. AMZN, +0.34% slumped 5.8% to $581.55.

Less affected but also in the red was Apple, down 2.5% to $97.37; as well as Alphabet Inc. GOOGL, +0.02% , down 3.5% to $719.57; Facebook, down 3.9% to $95.44; Microsoft Corp., down 2.1% to $51.64; and Tesla Motors Inc TSLA, +4.90% . , down 4.6% to $200.31.

Morgan Stanley downgraded the entire sector to underweight from market weight on Wednesday and said it was reducing its exposure to technology by 3%. Apple, LinkedIn Corp. US:LNKD and Palo Alto Networks Inc. PANW, +0.90% were among the stocks the brokerage retreated from, while it slightly raised its position in Alphabet.

Interestingly, Fitbit Inc. FIT, +0.38% , which has suffered steep selloffs and record levels of short interest in recent months, ended the day slightly higher. Its shares rose 1.1% to $19.85 despite tumbling 12% below its $20 IPO for the first time on Tuesday.

The market selloff comes at the start of earnings season, with Intel kicking off the tech-sector companies after the bell on Thursday.