IPO Investing Best Practices: What SpaceX Showed Us, and What to Know Before Anthropic

Two of the biggest stock offerings in history are now in the news cycle at once. SpaceX began trading on the Nasdaq on June 12, 2026, in what was reported as the largest IPO ever. Anthropic filed its public S-1 on October 26 and is reportedly preparing to price its own offering, though timing is unconfirmed. If you are tempted by either, the useful question is less "is this a good company?" and more "is the IPO itself a good way for me to own it?" Those are different questions, and the evidence on the second one is more sobering than the headlines.

What the SEC says in plain terms

The SEC's Office of Investor Education and Advocacy publishes an Investor Bulletin on IPOs, and it is worth reading in full. A few points from it frame everything below:

• Risk. "By their nature, however, IPOs can be risky and speculative investments." A newly public company usually has no trading history, so the prospectus is often the main source of information.
• Who gets the offering price. Clients of the underwriters may be offered shares at the offering price, and underwriters often distribute most of the shares to their institutional and high-net-worth clients. Most individual investors buy after trading starts, through a broker.
• The offering price is negotiated. It "may bear little relationship to the trading price," and the closing price shortly after an IPO can move sharply above or below it.
• Lock-ups. Insiders and early investors are often restricted from selling for a set period, typically 180 days. The bulletin warns that the share price "may decline significantly if a large number of shares become available for sale all at once" when those restrictions end.
• Dual-class stock. Super-voting shares can give founders control that makes it "more difficult, if not impossible" for public shareholders to influence decisions.
• No SEC endorsement. The SEC's declaration that a registration is effective "does not represent an approval of the merits of the IPO."

Case study: SpaceX, June to October 2026

SpaceX is the first mega-IPO of this cycle, which makes it a live test of every point above. The figures below come from press reports and a market-data aggregator, and the dates matter, so treat them as a timeline rather than a prediction.

Three lessons stand out. First, the first-day pop went to people who got shares at $135 or who sold quickly. Someone who bought at the day-one close of $161 was down about 32% at the Aug. 6 midday price of $109.86 and about 10% under water at $145.23. Second, the lock-up calendar was knowable in advance, and the 911.5 million shares eligible on August 6 were about 1.4 times the shares sold in the IPO itself. Third, the stock responded to its first earnings report, not to the IPO story: the prospectus gives you a snapshot, and quarterly results show whether the story is holding.

The track record of big IPOs

One sample is an anecdote. Here is a bigger, if still small, one. First Trust and Bloomberg data, cited in a Motley Fool article republished by Yahoo Finance, looks at the 15 largest U.S. IPOs since 2006 by market value at the offering price. The average stock returned -33% in its first year and fell 50% at some point along the way. Two of the 15, Airbnb and Snowflake, finished the first year up, and Visa finished flat.

Read that table with care. It covers 15 stocks, the source does not fully explain its method, and several of the worst results come from the 2021 peak. Coinbase listed directly rather than through a traditional IPO, though the source counts it. It does not say that every IPO falls, and good businesses can be poor stocks at a given price. Its message is narrower: the offering price and the first weeks of trading are not a bargain by default.

Eight practices worth following

• 1. Read the prospectus sections the SEC highlights. Among them: Risk Factors, Use of Proceeds, Dilution, and Shares Eligible for Future Sale. Check that you are reading the latest amended version, because terms change during registration. Our guide to reading a 10-K covers many of the same skills.
• 2. Know who is selling, and why. The prospectus shows how much of the offering is new money for the company and how much is existing holders cashing out. Both are legitimate, but they are different signals.
• 3. Find the lock-up calendar before you buy. Look for the dates, the share counts, and any early-release triggers, such as quarterly results. Compare the shares that unlock to the shares sold in the offering.
• 4. Do your own valuation arithmetic. Divide the market value at the expected price by trailing or annualized revenue, and compare it with mature companies. The multiple does not decide anything on its own, but it shows how much growth is already priced in.
• 5. Read the governance section. Who elects the board? Do public shares carry one vote or ten? What recourse do outside shareholders have? In dual-class structures, the answer can be "very little."
• 6. Be wary of chasing the first day. The first-day price reflects limited float and heavy demand. If you do buy, consider a limit order, which sets the maximum you will pay, so a volatile open cannot fill you at a spike.
• 7. Think about size. If you buy, consider the dollar amount you could watch fall 50% without changing your plans. See the arithmetic below.
• 8. Treat "pre-IPO" offers as a red flag. Anthropic and OpenAI have each published warnings, as reported by CoinMarketCap, that unauthorized sales of their equity through special purpose vehicles, tokens, or forward contracts may be void or have no value. If your only way in is a stranger's message, it is not a way in.

Where Anthropic fits

Anthropic's public S-1 was filed October 26. As of the filings and reports we reviewed, it has not set a price range, share count, or raise size. The filing proposes a Nasdaq listing under the ticker ANT, with Goldman Sachs and Morgan Stanley as lead bookrunners. Reports vary on timing: Bloomberg-sourced coverage, first reported before the public filing, points to marketing as soon as the week of November 9, which is not confirmed. The shape of the deal matters for each practice above: the lock-up is staged, the governance is unusual, and the valuation question is large. We cover those in detail in our Anthropic S-1 explainer, which includes a disclosure you should read first.

A final point on access. With SpaceX, reports said about 30% of the shares were earmarked for retail investors through brokerages, which was unusually high. Whether Anthropic's offering will offer comparable retail access in the U.S. has not been spelled out in what we reviewed. Check your broker's IPO-access program, and remember the SEC's note that most individuals end up buying in the open market.

A calmer way to own the theme

If the interest is in AI or space as a theme rather than in one ticker, broad index funds may add these companies once they meet index rules. SpaceX qualified for a fast-entry rule at the Nasdaq-100 but not for the S&P 500, which requires profitability and seasoning, per Reuters reporting compiled by Wikipedia. Our piece on index funds versus active management covers why many patient investors let that happen rather than race it.

Common questions

Can I buy shares at the IPO price?

Usually not directly. The SEC's investor bulletin says clients of the underwriters may be offered shares at the offering price, and that underwriters often distribute most of the shares to institutional and high-net-worth clients. Some brokerages run IPO-access programs, with their own eligibility rules, and most individual investors buy after trading begins.

What is an IPO lock-up?

A lock-up is a period after the IPO when insiders and early investors are restricted from selling. The SEC says 180 days is typical. SpaceX's lock-ups were staggered, with the first release on August 6 and others through December 8, and longer restrictions of 366 days for Musk, as reported. A lock-up ending does not force anyone to sell, but it adds potential supply.

Do IPOs usually go up on the first day?

Often, but not always, and the first-day price can differ sharply from the offering price in either direction, per the SEC. Gains on day one mostly go to people allocated shares at the offering price. For later buyers, the evidence in this article suggests the following year has been rough for many of the largest IPOs.

What should I read before buying an IPO?

Among the prospectus sections the SEC highlights are Risk Factors, Use of Proceeds, Dilution, and Shares Eligible for Future Sale. Add the governance and lock-up descriptions, and the most recent quarterly numbers.

Is it safe to buy pre-IPO shares from a third party?

Be very cautious. Anthropic and OpenAI have each warned that unauthorized sales of their equity, including through special purpose vehicles and tokenized products, may be void or have no value. Verify any seller against the company's own investor warnings page.