SpaceX stock rose on Monday ahead of another tranche of stock beingunlockedto trade.

Shares of Elon Musk’s rocket and artificial-intelligence company rose 4.5% on Monday, closing at $146.23, while the S&P 500 and Dow Jones Industrial Average both slipped about 0.5%.

The move came as about 319 million shares held by early investors and insiders become available to trade soon. SpaceX sold about 556 million new shares to the public in early June, raising about $75 billion (excluding the broker’s overallotment option), which was a small fraction of the roughly 13.2 billion shares outstanding.

Insiders and early investors are typically barred from selling stock for a while after an initial public offering. Sometimes those shares are unlocked after 180 days. SpaceX opted for a laddered approach, with relatively small amounts of stock unlocking at various intervals. About 912 million shares became available to trade on Aug, 6, and another 319 million will unlock on Aug. 20.

More than 700 million shares unlock in September, and more than 650 million unlock in October. By year-end, about 4.9 billion shares of SpaceX will become available to trade, which is roughly 70% of the stock not held by Elon Musk.

Supply and demand of SpaceX stock have dominated early trading. Investors have been wary of buying ahead of potential profit-taking by early investors, which is one reason SpaceX stock traded below $105 in July, far below the $135 IPO price. The stock recovered after a strong second-quarter earnings report on Aug. 4, and after the shares unlocked for trading on Aug. 6.

Shares rose 23% the week SpaceX reported earnings. The stock rose another 5% this past week, making it two weekly gains in a row for the space company. Before the gains, SpaceX stock had fallen for four weeks straight.