S-1 Filings Explained: How to Research IPOs Before They Go Public
Learn how to read S-1 registration statements to evaluate IPOs before they start trading. A complete guide to IPO research using SEC filings.
Right before a company goes public, there’s a moment where the information gap flips.
For years, only insiders and private investors had detailed numbers. Then, one day, the company drops a monster PDF on the SEC’s website that suddenly tells you almost everything: how the business works, how fast it’s growing, what it’s afraid of, who owns it, and how much they want public markets to pay.
That document is the S‑1 registration statement.
If you’re trying to evaluate an IPO, the S‑1 is the closest thing you’ll ever get to opening the hood before the car rolls onto the lot. Media coverage, banker decks, and hot‑take threads are just commentary; the S‑1 is the source.
This guide is about using that source properly—how to find S‑1s, what order to read them in, what to pull out, and which patterns should set off alarms before you get caught in IPO FOMO.
What an S‑1 Actually Is
Form S‑1 is the SEC’s standard registration statement for companies that want to sell securities to the public, usually for the first time.
In plain terms: before a company can do an IPO on the NYSE or Nasdaq, it has to convince the SEC, “Here’s who we are, here’s what we do, here’s our financial history, here’s what could go wrong, and here’s how this offering will work.”
A few core points:
- It’s filed before the IPO, often weeks or months in advance.
- It covers business description, financials, risk factors, management, ownership, and offering mechanics in one place.
- It’s iterative: you see an initial S‑1, then a series of S‑1/A amendments as the company responds to SEC comments and updates numbers.
- The same filing eventually morphs into the prospectus investors receive when the deal prices.
You can find S‑1s in the usual place (SEC EDGAR) or through a more usable front end like Earnings Feed’s filings view, which lets you filter by form type instead of wrestling with 1990s search.
The S‑1 Timeline: From “We’d Like to IPO” to “Now Trading”
Understanding the sequence helps you know where you are in the process when an S‑1 pops up.
Initial S‑1
This is the “we’re going public” moment. The company lays out historical financials, a full risk section, and a description of the business. The price range is often missing or just placeholder language. Timing is fuzzy; the company and its bankers are still feeling out demand and dealing with SEC questions.S‑1/A Amendments
Over the following weeks, you’ll see amended versions (S‑1/A). These may update recent quarterly numbers, tweak risk factor wording, add additional details the SEC asked for, and eventually include an actual proposed price range and share counts. Each amendment is a little closer to launch.Final Amendment with Price Range
When the S‑1 shows a real range (e.g., “we expect the price to be between $24 and $28 per share”) and more detailed offering terms, the IPO window is close—often within a week or two. At this point, the roadshow is typically underway.Effectiveness and Pricing
The SEC declares the registration “effective.” That’s the formal green light. The company and bankers then agree on an exact price, file the final prospectus, and trading usually begins the next day.
If you’re using a live filings tracker like Earnings Feed, the moment you see an S‑1 or S‑1/A for a name you care about, you know exactly where you are on that arc.
How to Read an S‑1 Without Getting Lost
Most S‑1s are 150–300 pages. If you try to read them front‑to‑back like a novel, you’ll hate your life.
A better approach is to read in layers, starting broad and only drilling down if the company passes your initial smell tests.
Layer 1: Prospectus Summary (First Pass)
The opening “Prospectus Summary” is your orientation. It usually covers:
- What the company does in one or two pages
- A sketch of the market opportunity
- High‑level financials (revenue, net income/loss, maybe key metrics)
- Basic offering details (shares offered, use of proceeds in bullet form)
In 10–15 minutes you should be able to answer:
- Do I understand, at a basic level, what this business does?
- Is it roughly profitable, roughly break‑even, or deeply loss‑making?
- Is growth obviously accelerating, obviously slowing, or not highlighted at all?
If the answer to “do I understand this?” is no, that’s already a decision: either dig in more because you’re curious, or accept that this might not be your game.
Layer 2: Risk Factors (Reality Check)
Next stop: the Risk Factors section. It’s long; it’s also where S‑1s are weirdly honest.
Companies are legally required to spell out material risks. Their lawyers would rather over‑disclose than under‑disclose, so you get:
- Customer concentration spelled out as “Customer A accounted for 32% of revenue.”
- Regulatory dependencies like “we rely on one key approval” in surprisingly direct language.
- Admissions that “we may never achieve profitability” or “we expect to raise additional capital in the future.”
Yes, there’s boilerplate (“we operate in a competitive market,” “our stock price may be volatile”). You can skim those. What you’re hunting for are risks that are:
- Specific to this company (not generic), and
- Potentially existential (not minor annoyances).
You’ll also learn how management and counsel think. A risk factor written in vague, hand‑wavy language about a very real business threat is not inspiring. One that is clear and detailed at least tells you they’re not in denial.
Layer 3: Business Section (How This Machine is Supposed to Work)
Once you’ve decided the company is at least interesting and not obviously a trap, go to the “Business” section.
This is the deep dive on:
- Products and services
- How they make money (pricing, contracts, subscription vs. transaction, etc.)
- Customer types and go‑to‑market strategy
- The competitive landscape they think they’re in
- Their stated growth strategy and “moat”
Here you’re trying to construct a mental model: what is the engine of this business?
For a SaaS company, it might be recurring seat‑based revenue plus upsells. For a marketplace, it might be take‑rates and transaction volume. For a biotech, it’s the pipeline and eventual economics of a successful drug.
If you can’t explain that engine in a few sentences after reading this section, you probably don’t understand it well enough to guess how it will behave as a public stock.
Layer 4: MD&A (How Management Tells the Story of the Numbers)
The Management’s Discussion and Analysis (MD&A) section is where you see how the people running the company interpret their own data.
They’ll walk through:
- Revenue trends and the underlying drivers
- Major expense categories and why they’re growing (or shrinking)
- Segment or cohort performance, if relevant
- Non‑GAAP metrics they consider important (ARPU, net dollar retention, LTV/CAC, etc.)
Two questions to hold in your head while reading:
- Does management have a sensible, consistent narrative for what the numbers are doing?
- Are they upfront about trade‑offs (for example, spending more on growth now at the expense of near‑term profitability)?
If the MD&A feels like it’s straining to avoid obvious issues—slowing growth, ballooning costs—that’s worth noting.
Layer 5: Financial Statements (The Cold Water)
Finally, you get to the actual numbers: income statement, balance sheet, cash flow statement, and associated notes.
This is where you sanity‑check the story:
- Is revenue growth as impressive (or not) as they keep saying?
- Are gross margins improving, stable, or deteriorating?
- How much are they spending on sales & marketing, R&D, and G&A as a percentage of revenue, and how is that changing?
- Are operating losses shrinking as a % of revenue, or widening?
- How much cash is on the balance sheet, and what’s the cash burn rate? How many quarters of runway do they have if nothing changes?
You don’t have to build a wonky model. A rough feel for trajectory—“growing 40% with improving gross margins and shrinking losses” vs. “growth slowing as losses expand”—goes a long way.
Things You Should Definitely Check Somewhere in the S‑1
There are a few sections that don’t fit neatly into the “read in order” flow, but are too important to skip.
Use of Proceeds
There’s a dedicated section where the company explains how it plans to use IPO money.
You’re hoping to see:
- Investment in growth (sales, product, expansion)
- Reasonable debt pay‑down
- General corporate purposes in a proportion that feels sane
Red flags include:
- Most of the proceeds earmarked to repay old debt that probably should have been refinanced earlier.
- Large chunks going to pre‑IPO investors or insiders cashing out. That’s not inherently evil, but if insiders are exiting aggressively on day one, ask why you’re supposed to be excited to get in.
Ownership and Lock‑Ups
The Principal Stockholders section shows who owns what before the IPO: founders, executives, VC funds, and other large investors.
A few things to look at:
- Will founders and management still own meaningful stakes after the offering?
- Are any of them selling in the IPO itself? If so, how much of their position?
- How concentrated is ownership in one or two funds?
You’ll often find language elsewhere about lock‑up periods (when insiders are restricted from selling). These dates matter; they can create additional supply months after the IPO when restrictions expire.
Capital Structure and Voting Rights
Many modern IPOs use dual‑class structures (for example, Class A with one vote, Class B with ten votes).
Ask yourself:
- After the IPO, who actually controls the company?
- Are you buying real influence, or just economic exposure with almost no say?
You might be fine with founder control. Just don’t discover it for the first time after something controversial happens.
Related‑Party Transactions
Buried in the back is a section on related‑party transactions—deals between the company and insiders or their affiliates.
This is where you see:
- The company leasing headquarters from an entity owned by the CEO.
- Loans to or from executives.
- Significant purchases or sales involving companies tied to board members.
These can be benign, especially in younger companies, but patterns of heavy self‑dealing are a governance smell.
Red Flags That Should Make You Slow Down
Not every IPO with issues is uninvestable. But some patterns in S‑1s deserve extra caution.
On the financial side:
- Growth decelerating sharply right before the IPO, with no convincing explanation.
- Gross margins trending down in a business that claims to have scalable unit economics.
- Operating losses widening faster than revenue grows, and no credible path to leverage.
- Heavy dependence on one or two customers for a large chunk of revenue, especially if that’s getting worse rather than better.
- A balance sheet that looks fragile even before the IPO proceeds hit.
On the structural side:
- A large portion of proceeds going to pay down ugly, expensive debt or to fund liquidity for insiders rather than the actual business.
- A capital structure that locks in control for a small group indefinitely, with very limited rights for public shareholders.
- A risk factor section that hints at unresolved regulatory questions or investigations in key markets.
None of these are auto‑nos. But they should move you from “this sounds cool” to “I’m going to assume the rosy scenario is a bonus, not a base case.”
Comparing S‑1s: When There’s a Mini‑Wave of Similar IPOs
S‑1s become even more useful when you look at them side by side.
If three payments companies or four SaaS security vendors file to go public in the same year, you can line up their disclosures and ask:
- Who’s actually growing fastest?
- Who has the best gross margins and the clearest path to operating leverage?
- Who has the most concentrated customer base?
- Who burns the most cash for each dollar of new revenue?
The sector stories—“the TAM is huge,” “the shift to X is inevitable”—start to look generic once everyone uses the same language. The numbers and specific disclosures are where you see separation.
Where to Find S‑1s Without Fighting the SEC Website
You can absolutely get S‑1s directly from SEC EDGAR. Search by form type (“S‑1”) and ticker or company name, and you’ll eventually find what you need.
If you’d rather not relive 1990s web design, you can also:
- Use Earnings Feed to filter the live SEC feed for S‑1 and S‑1/A filings as they hit EDGAR.
- Click through to a company’s profile and see its S‑1 alongside later 10‑Ks, 10‑Qs, 8‑Ks, and insider trades once it’s public.
Once the company is trading, its investor relations site will usually host the final prospectus and key S‑1 materials under “SEC Filings” or “IPO”.
A Practical IPO Research Workflow
You don’t need to turn every IPO into a multi‑day research project. A simple tiered workflow helps:
Quick Screen (30 minutes)
Read the prospectus summary and skim the financial highlights. Decide whether this is even in your circle of competence and whether growth/profitability is interesting enough to warrant more time.Risk and Business Pass (60–90 minutes)
Read the risk factors carefully. Then read the business section with a notebook open and try to write your own one‑paragraph description of the model. If you can’t, that’s telling.Financial and Structure Deep Dive (1–2 hours)
Go through MD&A and financials, focusing on growth, margins, and cash. Check use of proceeds, ownership, related parties, and voting structure. Make a short list of “pros,” “cons,” and “unknowables.”Valuation Context (around an hour)
Look at the proposed price range and implied market cap. Compare basic multiples (EV/revenue, maybe forward if guidance exists) to similar public companies, adjusted for growth and margin differences.Decision
At the end of this, you’re choosing between “buy at or after IPO if pricing is sane,” “watch but only touch after trading settles,” or “pass unless the valuation becomes absurdly cheap.” The point is that you’re making that call based on what the company itself disclosed, not just how loud the hype machine is.
Common IPO Traps
A few patterns are worth guarding against:
- Headline‑only research – Articles will emphasize narrative (“disrupting X,” “huge market”) and early investors. They rarely dwell on risk factors or unit economics.
- Assuming growth extrapolates forever – S‑1s often cover the best three‑year run a company has had. Growth almost always slows as the base gets bigger.
- Ignoring dilution and overhang – Stock‑based compensation, reserved option pools, and future fundraising will all eat into your slice of the pie. Lock‑up expirations can dump supply into the market months after the IPO.
- Treating “it popped on day one” as validation – Day‑one trading often reflects allocation dynamics and hype, not long‑term fair value. Missing the first candle rarely matters if you’re playing a multi‑year game.
The Point of S‑1s
The S‑1 is one of the few moments in a company’s life where you, as a public‑market investor, may actually know almost as much as the private investors who came before you. It’s dense; it’s legalistic; it’s also your best shot at understanding what you’re being asked to buy before the ticker exists.
If you’re serious about IPOs, treat the S‑1 as required reading. Everything else—interviews, presentations, hot takes—sits downstream from it.
If you want to make that easier to track:
- Create a free Earnings Feed account and add “S‑1” to the kinds of filings you care about in your watchlist.
- Use the live filings feed to see new IPO registration statements as soon as they hit EDGAR, not when they show up in a headline.
The SEC has already forced companies to show you their cards. Your job is to actually look at them before you bet.