Space Exploration Technologies Corp (SpaceX (SPCX)) is hitting a milestone today that could test the patience of even the most loyal shareholders. It's the 90-calendar-day early-release mark, and that means a big chunk of insider shares are now free to hit the market.

We're talking about roughly 319 million shares, or about 7% of the early release-eligible insider shares. Based on the Sept. 4 closing price of nearly $148, that's up to $47.2 billion in potential selling pressure. Yes, billion with a B.

SPCX Faces Resistance at $150 Level

SpaceX shares have been grinding higher, but they're bumping into a wall around $150. This resistance isn't random; it's where previous support levels used to be, and that's where sellers have placed orders to break even. Think of it as a ceiling made of people who bought higher and just want out at the same price.

If buyers can overpower those sellers and push the price above $150, it could signal a breakout and set the stage for a move higher. But if the unlock adds too much supply, that ceiling might hold.

Previous Share Unlocks Show Resilience

This isn't SpaceX's first rodeo with insider unlocks. Since its record-breaking June initial public offering, the company has already weathered two rounds. And here's the interesting part: the stock has stayed well above its IPO price of $135 through it all.

The first unlock on Aug. 6 actually saw shares rally instead of decline. The second, smaller unlock on Aug. 20 caused only a temporary wobble. As of Tuesday, shares were still trading comfortably above the IPO price.

So the big question is whether this third unlock will keep the streak alive or finally test investor demand. With $47.2 billion in potential selling pressure hanging over the market, today's price action will be telling.