Musk has taken on all three of America’s telecom giants at once. SpaceX announced it would spend around $8 billion to buy nationwide low-band spectrum licenses from Grain Management. With the final piece of the puzzle in place, it’s heading straight for the mobile carrier business—now it just needs the FCC’s approval.

The news sent all three stocks tumbling. T-Mobile plunged 13% in a single day, while Verizon fell nearly 9%—its worst one-day drop since 2002. The sell-off looked pretty alarming, while SpaceX itself edged up slightly.

The irony is that just last week, the three companies teamed up to form a satellite-to-phone joint venture—without SpaceX. Now SpaceX is going it alone, putting up its own money. T-Mobile, which took the biggest hit, is also the most profitable of the three. If Starlink really starts sending signals directly to phones, the carriers’ cell-tower business will be much harder to defend.