I'm Not Buying SpaceX on Day One: What the 19% Pop and the December Lockup Say About Timing

Will the forced buying crash the market? Let's kill this fear first

On the surface it sounds logical. SpaceX gets forced into the funds, those funds have to buy billions of it, so they have to sell billions of everything else they already own. That selling drags the other stocks down, the indexes follow, and your 401k bleeds red.

Clean story — but in my view it's wrong, and the reason is the size of the numbers.

Everything the funds are actually forced to buy adds up to roughly $8 to $12 billion. That feels huge until you set it next to a U.S. stock market worth more than $75 trillion. Do the division and the forced buying comes out to about 0.01% — one-hundredth of a single percent, basically a rounding error. The selling that pays for it gets spread so thin across so many giant stocks that almost nobody feels it.

We've run this experiment before. When Tesla was forced into the S&P 500, the buying was several times larger than what SpaceX will trigger, and the broad market barely moved. The dominoes everyone braced for never fell.

That doesn't mean nobody gets hurt: the December rebalance

A small group quietly pays the price when a giant muscles its way in.

But SpaceX doesn't directly shove anyone out. When the Nasdaq rewrote its rules, it wrote in that a giant entering this way forces no one out — the index simply carries more than 100 names for a little while. No company gets knocked off the island on day one.

The real test comes not from SpaceX but from the annual December rebalance, when the companies that have shrunk to the bottom get cut. When a data company called CoStar got dropped from the Nasdaq this spring, the stock had already fallen more than 60% by the time it was official. The market saw it coming and priced it in.

The core read: the day-one pop is bait

I'm not buying SpaceX on day one, and it's not because I doubt space — I do believe in it. It's that no company is worth almost a hundred times its revenue. So I take the emotion out and let history make the call.

The typical IPO pops about 19% on average on day one. That pop is the bait that pulls everyone in. But over the following year, IPOs tend to underperform.

Look at Robinhood. It more than doubled in its first week, then fell almost 90% from that peak a year later.

Why this keeps happening: the lockup

The reason is surprisingly simple. It's the lockup.

Everyone who owned the stock before the IPO is frozen out of selling a single share for about six months. For SpaceX, that lands in December. Once that clock runs out, all those shares can finally hit the open market — and I guarantee people will line up to cash in.

That makes December the window I'm watching.

My actual plan

Here's the summary. I'm not buying SpaceX on day one. The forced buying isn't large enough to crash the market, and it doesn't immediately push anyone out. But the price is expensive, and that day-one 19% pop only makes an expensive price more expensive.

My plan is to strip out the emotion and wait for the selling pressure when the lockup lifts in December. That's when there's a real window to weigh a fair entry on the facts. Not panic, not chasing — just a question of timing.

For the record, this is educational only and not financial advice. I'm not a financial advisor.