U.S. technology stocks extended declines in pre-market trading Wednesday as investors continue to fret over the prospect of tighter regulation  following Facebook Inc.'s (FB) - Get Report data scandal and two fatal accidents linked to self-driving cars that have shaken faith in the market's star sector.

The NYSE FANG+ Index, which tracks the moves of ten of the biggest and most active tech stocks in the world, slumped 5.63% Tuesday to a six week low of 2441.50 points, taking $180 billion in market cap along with it and taking the benchmark of big tech stocks into correction territory from its March 12 peak. The broader S&P 500 Information Technology index was also sharply lower, falling 3.47% yesterday to wipe out all of its gains for the year.

Many of the stocks in the equal-weight index were also moving lower in pre-market trading again today, with Facebook marked 0.81% to the downside, Netflix Inc. (NFLX) - Get Report marked 0.66% lower and Alibaba Holdings (BABA) - Get Report trading 0.34% to the downside. Telsa Inc.  (TSLA) - Get Report , however, was the standout decline, falling 1.28% to indicate an opening bell price of $275.50, the lowest in nearly a year. 

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Telsa is suffering following news that a fatal crash of one of its Model X vehicles in California last week has prompted an investigation from the U.S. National Transportation Board. Further pressure came from Moody's Investors Service, which lowered its credit rating on the clean energy carmaker deeper into junk status and warned that it faces "liquidity pressures due to its large negative cash flow and the pending maturities of convertible bonds."

Chipmaker Nvidia Corp. (NVDA) - Get Report , which fell 7.76% yesterday after it said it suspended tests on self-driving cars following the death of a pedestrian in Arizona last week, was marked 0.46% to the downside at $224.50 each in pre-market trading. 

Facebook shares were also slipping, falling 1.13% to indicate an opening bell price of $150.50 each, the lowest in 10 months and a move that would take the stock 21 lower from its early February peak. Apple Inc. (AAPL) - Get Report was marked 0.74% lower at $167.10.

Twitter Inc. (TWTR) - Get Report shares, which slumped 12% yesterday after a note from Citron Research warned that the social media group's business model of selling user data could trigger a sharper regulatory response than its rivals, was marked 0.89% lower at $27.82 each.

The Stoxx Europe 600 Technology index, the sector benchmark, was marked 2.73% lower at 423.34 points, taking the year-to-date decline to 3.56%, with Tesla Inc. (TSLA) - Get Report supplier Infineon AG falling 4.6% (IFNNY) , chipmaker AMS AG (AMSSY) tumbling 7.8% and STMicroelectronics NV (STM) - Get Report declining 4.73%.