Virgin Galactic Holdings (NYSE: SPCE) chairman Chamath Palihapitiya has sold a significant portion of his stake in the company, a move that is likely to further pressure shares of the space tourism start-up. According to a regulatory filing Palihapitiya sold 6.2 million shares at an average price of $34.32 per share, raising $213 million. He still owns 15.8 million shares, or about 6.2% of the company, along with investment partner Ian Osborne. Palihapitiya and Virgin Galactic helped kick off the wave of start-ups going public via special purpose acquisition companies, or SPACs. The company went public in October 2019 via a merger with Palihapitiya's Social Capital Hedosophia, and until recently had been a top performer. Image source: Virgin Galactic. Virgin Galactic has a roster of hundreds of clients signed up to pay $250,000 for a brief flight to the edge of space, but the company is behind schedule in getting them there. A combination of pandemic-related delays and some testing setbacks forced Virgin Galactic to miss its 2020 goal to begin service. The company expects to launch service this year, but has experienced some delays in its testing schedule. Until recently, none of those setbacks mattered for the stock. Virgin Galactic shares climbed nearly 150% in the first six weeks of 2021, but the momentum has faded in recent weeks. The shares are down 49% since Feb. 11 heading into Friday morning trading, and are down another 5% in premarket action. Virgin Galactic on Thursday also announced the departure of chief space officer George Whitsides, who is leaving to pursue potential opportunities in public service. Whitesides, a former Chief of Staff at NASA, was CEO of the company through much of its development. 10 stocks we like better than Virgin Galactic Holdings IncWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Virgin Galactic Holdings Inc wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of February 24, 2021 Lou Whiteman has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Virgin Galactic Holdings Inc. The Motley Fool has a disclosure policy.Source