Stocks making the biggest moves in the premarket: Virgin Galactic, Moderna, AMC Entertainment & more
Take a look at some of the biggest movers in the premarket:

Virgin Galactic (SPCE) – Virgin Galactic soared 20.5% in premarket trading after it held a successful test flight over the weekend of its SpaceShipTwo craft. Virgin's first manned space flight in more than two years successfully reached space 50 minutes after takeoff from Las Cruces, New Mexico, before returning to earth.

Martin Marietta Materials (MLM) – Martin Marietta struck a deal to buy the California and Arizona assets of Germany's HeidelbergCement for $2.3 billion in cash. The construction materials company will acquire 17 quarries and two cement plants as part of the deal, among other assets.

Cabot Oil & Gas (COG) – Cabot and rival oil and natural gas producer Cimarex Energy (XEC) agreed to an all-stock merger of equals valued at $7.35 billion. Cimarex shareholders will receive a little over four shares of Cabot for each share they now own. Cabot shares added 1.9% in premarket trading, while Cimarex stock was up 0.4%.

CureVac (CVAC) – The drugmaker is working to expand production capacity for its Covid-19 vaccine in anticipation of a June European Union approval, according to a company spokeswoman quoted in a German newspaper.

Moderna (MRNA) – Moderna struck a vaccine production agreement with South Korea's Samsung Biologics, in a move it said will allow it to provide its Covid-19 vaccine to markets outside the United States beginning in the third quarter. Its shares climbed 1.6% in premarket action.

AMC Entertainment (AMC) – AMC's largest shareholder, China's Dalian Wanda Group, sold most of its stake in the movie theater operator over the past week. A Securities and Exchange Commission filing shows Dalian Wanda sold 30.4 million shares for about $427 million. AMC shares rose 1.5% in the premarket.

GlaxoSmithKline (GSK) – The British government is concerned about a possible takeover of GlaxoSmithKline, according to the Times of London newspaper, and has asked officials to monitor the situation. The concern was sparked by an investment in Glaxo by activist hedge fund Elliott Management.

HP Inc. (HPQ) – The computer and printer maker's shares rallied 2.3% in premarket action after Citi upgraded it to "buy" from "neutral." Citi expects HP to beat consensus Street forecasts and raise its outlook when it reports later this week, as it benefits from upbeat fundamentals in the PC space.

Coinbase (COIN) – Coinbase remains on watch as the operator of the largest U.S. cryptocurrency exchange continues to trade in a volatile manner, reflecting wide swings in the digital currencies. It rose 2.3% in premarket trading after a newly initiated "buy" rating at Goldman Sachs, which notes the company's leading position in a rapidly expanding market.

Beyond Meat (BYND) – The maker of plant-based meat alternatives received a double upgrade at Jefferies to "outperform" from "underperform," based on an expected recovery in organic growth and rebounding foodservice channels. Beyond Meat gained 3.7% in premarket action.

Dollar General (DG) – The discount retailer's shares fell 1.4% in the premarket after Bank of America Securities downgraded the stock to "underperform" from "neutral." The firm notes that Dollar General stock historically has been pressured in times of rising gasoline prices, and that customer traffic could be hurt by rebounding use of gas station convenience stores.

Palantir Technologies (PLTR) – The data analytics platform company won a $32.5 million contract to provide its software to the Air Force and Space Force. Its shares rose 1% in premarket trading.