Before SpaceX or Anthropic sells a single share to the public, every investor in the world will get a chance to read their financial secrets. Here’s how to use that window.

More than 6,700 companies have gone public in the U.S. since 2000, and every single one filed the same document before their shares hit the market. Most retail investors never read it. That’s a mistake, especially right now, with SpaceX having confidentially filed its S-1 in early April 2026 at a potential $1.75 trillion valuation, and Anthropic reportedly eyeing a Q4 2026 IPO that could raise tens of billions.

If you’re an entrepreneur or angel investor and have been nodding along without fully knowing what an S-1 actually contains, this is your primer.

The Basics

An S-1 filing (officially SEC Form S-1) is the registration statement U.S. companies must submit to the Securities and Exchange Commission before selling shares to the public in an IPO. Required under the Securities Act of 1933, it functions as the official prospectus, giving investors a detailed look at the company’s business, finances, and risks before a single share changes hands. Without an effective S-1, a company can’t legally list on the NYSE or Nasdaq.

One nuance worth understanding: companies classified as “emerging growth companies” (EGCs) can submit a confidential draft registration statement first, receiving SEC feedback privately before anything goes public. That’s exactly what SpaceX did in April. It lets companies gauge regulatory appetite without tipping off competitors or triggering premature media speculation.

What’s Actually Inside?

S-1 filings run hundreds of pages, but they follow a standardized structure. Part I is the investor-facing prospectus, the section that actually matters to you. It covers the business description, market opportunity, and competitive landscape; the Risk Factors section, where companies are legally required to disclose every material threat to the business; the Management’s Discussion and Analysis (MD&A), where executives explain the financials in their own words; audited financial statements; how the company plans to deploy the IPO proceeds; and executive compensation and proposed offering terms. Part II handles technical exhibits most retail investors will skip.

All of it is governed by SEC disclosure rules: Regulation S-K for narrative disclosures and Regulation S-X for financials. The goal is full transparency before the market opens.

Start with the Risk Factors section. It’s the most honest part of any S-1, and companies are legally on the hook for what they include.

From Filing to First Trade

Getting from “we want to go public” to “shares are trading” typically takes six to twelve months. The company spends the first one to two months drafting the document alongside outside securities lawyers, investment bankers, and auditors. EGCs can then submit a confidential draft to the SEC, which generally responds within about 30 days. The full back-and-forth review process often runs 75 to 120 days total. Once the public filing goes live, the company must wait at least 15 days before beginning its investor roadshow. After the roadshow, the SEC declares the S-1 “effective,” shares price, and trading begins.

SpaceX is targeting a June or July 2026 debut following its April filing, right on schedule for this timeline.

How to Read One Yourself

Anyone can access S-1 filings for free through the SEC’s EDGAR database at sec.gov/edgar. Search by company name, filter for “S-1” or “S-1/A” (amendments filed during the review process), and you’re in. It’s the same database professional analysts use; no paywall, no premium tier.

A practical exercise: pull S-1s from companies in your industry to benchmark financials, study how competitors frame their risk factors, and understand how comparable businesses describe their competitive moats. The information is sitting there. Most investors just don’t look.

What an S-1 Won’t tell you

The S-1 is a disclosure document, not a sales pitch. Companies can redact competitively sensitive information, including certain contracts, customer lists, and trade secrets, with SEC approval. Forward-looking statements come with safe harbor disclaimers precisely because projections frequently miss. And the audited financials are historical: they show where the company has been, not where it’s going.

The S-1 is a window into a company’s past and present. Sizing its future is still your job.

Why 2026 Could be a Turning Point

IPO activity tracks closely with market confidence, and the swings are dramatic. The record was set in 2021 with 1,035 IPOs, heavily driven by SPACs. The floor was 2008 with just 62 IPOs during the financial crisis. Activity has been rebuilding: 225 IPOs in 2024, 347 in 2025. If SpaceX and Anthropic both cross the finish line this year, they won’t just be headline events; they’ll likely pull a wave of private companies off the sidelines that have been waiting for the right moment to file.

For angel investors and founders watching the IPO market, that’s the real story behind these S-1 filings. The biggest companies going public tend to lift the whole market’s appetite for new listings. Bookmark EDGAR, read the SpaceX S-1 when it drops publicly, and you’ll have more context than most of the people watching the ticker on day one.

Go Deeper

If the SpaceX or Anthropic IPO has you thinking about how private markets actually work, secondary markets are worth understanding before either company goes public, they’re already how sophisticated investors are getting in before the S-1 even drops. And if you end up holding equity in either deal, the K-1s, capital accounts, and basis tracking that come with it are concepts worth getting comfortable with now. For the bigger picture on how companies raise money before they ever reach the IPO stage, the personal finance and funding fundamentals are a good place to start.