How to Read a US S-1 Filing: The 5 Sections Indian Investors Must Check

Before you invest in any US IPO, the company has already told you everything you need to know. It is all in a document called the S-1 filing, available for free on the SEC website. This guide walks you through the five sections that matter most and shows you exactly what to look for in each one.

What is an S-1 Filing? (The US Equivalent of India's DRHP)

If you have tracked an Indian IPO before, you may have come across the term DRHP (Draft Red Herring Prospectus). The S-1 is its American equivalent. Before any company can list its shares on a US stock exchange like the NYSE or NASDAQ, it must file an S-1 with the Securities and Exchange Commission (SEC). 

This document contains the company's full business description, three years of audited financial statements, risk disclosures, and details on how the IPO proceeds will be used.

An S-1 can run anywhere from 200 to 500 pages. You do not need to read all of it. Once you know where to look, five sections give you everything you need to make an informed decision.

S-1 vs DRHP: 5 Key Differences Indian Investors Must Know

One important difference worth noting: the S-1 requires a section called MD&A (Management Discussion and Analysis) where management must explain every major financial trend and why it happened. This is often where the most useful information sits, beyond the raw numbers themselves.

Where to Find Any S-1 Filing Free on SEC EDGAR

EDGAR (Electronic Data Gathering, Analysis, and Retrieval) is the SEC's free public database. Here is how to find any S-1 in under two minutes:

1. Go to sec.gov.
2. Click on EDGAR in the top navigation bar.
3. Use Company Search and type the company name.
4. Filter by filing type: S-1.
5. Select the most recent filing to open the document.

The filing opens as an HTML document or a PDF..

What is an F-1 Filing? (For Non-US Companies Listing in America)

If a company was incorporated outside the US but wants to list on the NYSE or NASDAQ, it files an F-1 instead of an S-1. The content is nearly identical. Spotify filed an F-1 when it listed in 2018 because it is a Swedish company. Alibaba filed an F-1 before its 2014 NYSE listing as a Chinese company. If you are researching a foreign company listing in America, look for an F-1 rather than an S-1.

Section 1: Business Overview — Understand the Model First

The Business Overview is usually one of the first major sections in an S-1. It describes what the company does, who it sells to, how it makes money, and what market it competes in.

Read this section with one goal in mind: can you explain the business in a single sentence after you finish? If the answer is no, that is a warning sign. A business you cannot explain simply is often one whose complexity hides weak fundamentals.

Examples of clear one-sentence explanations:

• Airbnb: "An online platform where homeowners rent their properties to travellers."
• Instacart: "A grocery delivery service that connects shoppers to stores in their city."

If you cannot write something similar after reading the Business Overview section of an S-1, approach the IPO with more caution.

Total Addressable Market (TAM): Is the Market Big Enough?

TAM is the total revenue a company could generate if it captured its entire target market. Example: a company building HR software for mid-sized US businesses estimates there are 200,000 companies spending an average of $10,000 per year on HR tools. TAM = $2 billion.

What to check in the S-1:

• Is the TAM built on realistic assumptions? Companies often present optimistic maximum-case figures. Look at how they define the market boundaries.
• Is the market itself growing or shrinking? A large but declining market limits long-term potential regardless of how good the product is.
• What share of the TAM does the company hold today? A claim of a $500 billion TAM alongside $50 million in revenue needs a credible, specific growth path to be meaningful.

A large TAM alone does not guarantee success. But a small TAM places a hard ceiling on how big the company can ever grow.

Competitive Moat: What Stops Someone from Copying This?

A moat is whatever makes it difficult for a competitor to take the company's customers. The Business section often describes it, but sometimes you have to read between the lines. Common types to look for:

• Network effects: the more users a platform has, the more valuable it becomes. Payment networks, social platforms, and marketplaces benefit from this.
• Switching costs: customers would face significant cost, effort, or data loss if they moved to a competitor. Enterprise software is a classic example.
• Intellectual property: patents, proprietary technology, or unique algorithms competitors cannot legally replicate.
• Brand: consumer trust built over years. Hard to copy quickly.
• Distribution advantage: exclusive partnerships, regulatory licences, or supply chain relationships competitors cannot easily match.

A Business Overview that cannot point to at least one of these is describing something anyone with enough capital could replicate.

Section 2: Risk Factors — The Most Underread, Most Important Section

Most investors skim or skip the Risk Factors section. That is a mistake. This is where the company is legally required to disclose every material risk. Because they are held to a standard of legal accuracy here, these disclosures are useful in a way that marketing materials are not.

Two types of risks appear in this section. Generic boilerplate language that every company includes, such as "macroeconomic conditions could adversely affect demand," is standard filler. The specific, company-level disclosures that reveal real operational or structural vulnerabilities are what you should focus on.

Customer Concentration Risk: The #1 Red Flag for Indian Investors

Customer concentration risk is when a significant share of a company's revenue comes from just one or a few customers.

The CoreWeave S-1 (filed in early 2025) disclosed that Microsoft accounted for approximately 62% of its total revenue. A significant change in Microsoft's spending with CoreWeave would cut the company's revenue by more than half. This is an extreme example, but concentration risk is common in early-stage companies that grow by landing one or two large enterprise clients.

As a rule of thumb:

• One customer contributing more than 30% of revenue = high concentration risk.
• Two or three customers together making up more than 50% of revenue = high risk.

Search for "customer concentration" or "significant customers" in the Risk Factors section. Many S-1s also include a dedicated table showing top customers by revenue percentage.

Material Weaknesses in Internal Controls

A material weakness is a failure in a company's accounting or financial reporting processes, formally identified by the independent auditors. It signals that financial statements may not be fully accurate and that management may not have tight control over their own finances.

This matters for two reasons. First, if the numbers cannot be fully trusted, any analysis based on them becomes unreliable. Second, repeated material weaknesses often indicate a company that is not operationally ready for the demands of being publicly listed.

Search for "material weakness" in the Risk Factors section or within the auditor's report inside the financial statements. One material weakness is a yellow flag. Multiple are a red flag.

Going Concern Language

A going concern qualification means the independent auditors have formally expressed doubt about whether the company can survive over the next 12 months.

The exact phrase to search for: "substantial doubt about the company's ability to continue as a going concern."

If you find this language anywhere in the S-1, treat it as a serious warning signal. It does not guarantee the company will fail, but it means the auditors could not confirm it will survive. For most investors, this is reason enough to pass on the IPO.

Make "going concern" your first Ctrl+F search on any S-1 before doing anything else.

Section 3: Use of Proceeds — Where Is the IPO Money Actually Going?

The Use of Proceeds section is typically only one or two pages long, but it is one of the most revealing parts of the entire S-1. It tells you exactly what the company plans to do with the money it raises from new investors.

Growth Capital (Like India's Fresh Issue) vs Insider Cashout (Like OFS)

In any IPO, the money raised moves in one of two directions.

Fresh capital (the Indian equivalent of a fresh issue) is new money that flows directly into the company's accounts. Management plans to use it for R&D, infrastructure, hiring, or expansion. This is a positive signal. The company is raising capital to grow, not just providing an exit for insiders.

Selling shareholders (the Indian equivalent of an Offer for Sale, or OFS) means existing shareholders, including founders, venture capital firms, or private equity investors, are selling their shares through the IPO. The money goes to them, not to the company. A high proportion of selling-shareholder proceeds indicates insiders are primarily using the IPO as an exit rather than funding the business's future.

Note: some level of selling-shareholder activity is normal. Founders and early investors are entitled to liquidity after years of building the company. The concern is when this proportion is large and the fresh issue component is small.

Red Flag: 'General Corporate Purposes' as a Vague Catch-All

It is standard practice for an S-1 to include some allocation for "general corporate purposes." This gives management flexibility for unexpected needs and is not unusual in itself.

The concern arises when a large portion of the proceeds carries this label with no specific breakdown. If more than 25% of total IPO proceeds are assigned to "general corporate purposes" without further explanation, management has not been transparent about how they plan to deploy the capital you are being asked to provide.

Section 4: Financial Statements — The 4 Numbers That Matter

US S-1 filings must include three years of audited financial statements. This is the most data-rich section in the document. You do not need to analyse every line. Four metrics give you most of what you need to assess the financial health of the business.

Revenue CAGR: 3-Year Trend (Not Just Last Year's Number)

CAGR stands for Compound Annual Growth Rate. It measures how fast a company's revenue has grown on average over a period of time.

Why look at three years instead of just the most recent number: a single strong year can reflect a one-off contract, a favourable market event, or an acquisition. Three-year CAGR shows the underlying growth trajectory more reliably.

Formula: CAGR = (Revenue in Final Year / Revenue in First Year) ^ (1 / Number of Years) - 1

Example: a company with $100 million in Year 1 revenue and $196 million in Year 3 has a 3-year CAGR of approximately 40%.

What to look for: consistent growth across all three years, not one spike followed by flat results. A revenue decline in any year warrants a specific explanation from management in the MD&A section.

Gross Margin Trend: Expanding = Positive, Compressing = Warning

Gross margin is the percentage of revenue that remains after deducting the direct cost of delivering the product or service.

Formula: Gross Margin = (Revenue minus Cost of Goods Sold) / Revenue, expressed as a percentage.

Example: a software company earns $200 million in revenue with $40 million in direct delivery costs. Gross margin = ($200M - $40M) / $200M = 80%.

What the trend tells you:

• Rising gross margin over three years: the company is gaining pricing power, improving efficiency, or shifting to higher-margin products.
• Falling gross margin over three years: costs are rising faster than revenue, competition is forcing prices down, or the business has scaling problems it has not resolved.

A high gross margin is good. A consistently expanding gross margin over three years is better.

Cash Flow from Operations: The Most Reliable Profitability Signal

Net profit is an accounting figure. It is calculated using rules that include non-cash items and timing adjustments. Cash flow from operations shows what is actually coming into and going out of the company's bank account from running its core business.

A company can report an accounting profit while still burning real cash. This happens when customers have not yet paid outstanding invoices, inventory builds up faster than it is sold, or when aggressive revenue recognition policies record income before cash actually arrives.

What to look for:

• Positive operating cash flow: the business generates real cash from its core operations, not just accounting profits.
• Positive net profit but negative operating cash flow: investigate further. Something is distorting the reported income figure.
• Growing operating cash flow year over year: the most reliable sign of improving business health.

Debt Load vs Cash on Balance Sheet

Pull two numbers from the balance sheet: total debt and total cash (including cash equivalents).

Key signals to watch:

• Total debt exceeding twice annual revenue is significant leverage, especially dangerous for a company that has not yet reached profitability.
• Cash raised through the fresh issue must realistically fund operations until the business reaches breakeven or its next planned funding round.

Example: a company raises $500 million in its IPO and retains $200 million for operations. It carries $150 million in existing debt and burns $50 million in cash per quarter. That is roughly four quarters of runway before it needs to raise more capital. If the path to profitability is not clear within that window, existing investors will face dilution when the company returns to the market.

Section 5: Insider Ownership, Lock-Up Details and Compensation

This section answers three questions: do the people running the company have meaningful financial stakes still at risk? When can they sell their shares? And how are they being paid day to day? Together, the Principal Stockholders table, the Lock-Up section, and the Executive Compensation disclosures tell you whether management's interests are aligned with yours as a new shareholder.

Founder Post-IPO Stake: How Much Are They Keeping?

Look for the Principal and Selling Stockholders table. It shows who owns the company before the IPO and what percentage each person or entity will hold after it.

The signal is straightforward: founders retaining 20% or more of the company post-IPO have significant personal wealth tied to the stock price. Their financial interest is aligned with yours. Founders selling the majority of their stake in the IPO are prioritising their own liquidity over the company's future. This is a caution flag.

Some founder selling is normal and expected. The concern is when the sale proportion is high relative to what they keep.

Lock-Up Period Details: Who Is Restricted and Until Exactly When?

A lock-up period is a contractual restriction that prevents company insiders, including founders, executives, employees, and early investors, from selling their shares for a set time after the IPO. Most US IPOs carry a 180-day lock-up (six months). Some have 90-day windows or tiered structures with phased release dates.

Why this matters for you: when a lock-up expires, a large number of shares suddenly become eligible for sale in the market. This often creates selling pressure and can push the stock price lower in the weeks around the expiry date.

What to check:

• Which shareholders are subject to the lock-up. Not all shareholders may be restricted equally.
• Exact lock-up expiry dates, not just the duration in days.
• Early release conditions. Some agreements allow insiders to sell earlier if the stock trades above a certain price for a set number of consecutive days.

Note the lock-up expiry dates when you first research any IPO. They are important markers for how the stock may behave in the months following the listing.

Executive Compensation: Salary vs Stock Options

The Executive Compensation section discloses what the CEO, CFO, and other key executives earned in base salary, bonuses, and equity-based compensation such as stock options or RSUs (Restricted Stock Units).

What you are looking for is how management's personal incentives are structured. Heavy equity-based compensation means management's personal wealth rises and falls with the share price. Their interest and yours are aligned. High base cash salaries in a company that has not yet reached profitability means management is drawing personal income before the business has earned it. This is a warning, not a dealbreaker, but it is worth noting.

A useful signal: well-run early-stage companies often pay executives below-market cash salaries while compensating them primarily in equity. This signals that management believes in the company enough to stake their own financial outcome on its performance.

S-1 Red Flags Checklist: 6 Things That Should Make You Pause

Use this as a quick filter before committing time to deep research on any US IPO.

No single flag automatically rules out an investment. But each one is a reason to ask harder questions before committing capital.

How Long Does It Take to Skim an S-1?

A focused first-pass reading of an S-1 takes 40 to 45 minutes once you know where to look. Follow this sequence

1. Search "Use of Proceeds" — read this section first to understand where the money goes. Approximately 5-10 minutes.
2. Search "Risk Factors" — scan for specific, company-level risks and skip generic boilerplate. Approximately 10-15 minutes.
3. Search "Going Concern" — if the phrase appears, reconsider immediately. Approximately 2-3 minutes.
4. Search "Lock-Up" — note exact expiry dates and any early release conditions. Approximately 3 minutes.
5. Open the financial statements — check revenue, gross margin, and operating cash flow across three years. Approximately 15-20 minutes.

Total: approximately 40-45 minutes. After this scan, you will know whether the company deserves deeper research or whether a red flag means you can move on without spending more time on it.