What Is an IPO?

IPO stands for initial public offering. It is the first time a private company offers its shares to the general public, listing them on a stock exchange like the Nasdaq or the New York Stock Exchange so that anyone can buy and sell them. The word “initial” matters: it is the company's debut on the public market, the single moment it crosses from private to public.

Before an IPO, a company is privately held. Its shares are owned by some mix of founders, employees, venture capital firms, and other private investors, and those shares are hard to buy or sell because there is no open market for them. After the IPO, the company is publicly traded: its ownership is split into shares that change hands all day long at a price the market sets, and the company has to report its finances regularly to regulators and shareholders. Going public is what turns a private business into a stock you can find a ticker for. If you are new to terms like ticker, share, and exchange, our stock market terminology guide defines the basics.

The first reason is to raise money. In a traditional IPO the company creates and sells new shares, and the cash from those sales goes onto its balance sheet. It can use that capital to expand, hire, build factories, pay down debt, or fund research. For a fast-growing business that has outgrown what private investors will provide, the public market is simply the largest pool of capital available.

The second reason is liquidity. Founders, early employees, and venture investors often hold shares for many years with no easy way to sell them. An IPO creates a public market where those shares can finally be converted to cash, which rewards the people who took early risk and helps the company attract talent with stock that has real, tradable value. Beyond money, going public raises a company's profile, subjects it to the discipline of public reporting, and gives it publicly traded stock it can use as currency to acquire other businesses. The trade-off is real: public companies face heavy regulation, constant scrutiny of quarterly results, and pressure from shareholders.

A traditional IPO is a months-long process with a fairly standard sequence. First, the company hires investment banks to act as underwriters. The underwriters help value the company, decide how many shares to sell, drum up demand, and often commit to buying the shares to resell them. The lead bank is called the bookrunner.

Next, the company files an S-1 registration statement with the Securities and Exchange Commission. The S-1 is a long, detailed document that lays out the business model, financial statements, how the money raised will be used, who the major shareholders are, and a frank list of risk factors. It is the single best primary source on a company about to go public, and it becomes public for anyone to read. Then comes the roadshow: executives travel (or present virtually) to pitch large institutional investors such as mutual funds and pension funds, gauging how much they would buy and at what price.

Using that feedback, the underwriters set the IPO price and the number of shares the night before trading begins. The next morning the stock opens on the exchange and starts trading freely, often at a price quite different from the set IPO price because public demand can be stronger or weaker than the banks estimated. Finally, a lock-up period (commonly 90 to 180 days) keeps insiders from dumping their shares immediately, so the new stock is not swamped by selling in its first months.

Here is the part that surprises people: most everyday investors cannot buy shares at the IPO price. Those shares, the ones priced at the headline number, are allocated mainly to the underwriting banks' biggest clients, which means large institutions and a handful of favored, high-net-worth individuals. By the time a regular investor can place an order, the stock is already trading on the open market, often at a price well above (or sometimes below) the IPO price set the night before.

That gap is why chasing a hot IPO on its first day can be risky: the easy gain may have already gone to institutions who bought at the offer price. Some brokers now offer limited IPO access to retail customers through allocation programs, but the share counts are small, eligibility rules apply, and an allocation is never guaranteed. For most people, the practical reality is that you buy an IPO stock the same way you buy any other stock, on the open market once it is trading, and you should size it like the volatile new position it is. You can look up an individual stock once it is public to study what little trading history exists.

A traditional IPO is not the only way to go public. In a direct listing, a company puts its existing shares straight onto an exchange without underwriters setting an offer price and usually without raising any new money. It suits companies that are already well known and do not need cash, and it avoids the underwriting fees and the gap between the IPO price and the first trade. Spotify, Coinbase, and Slack went public this way.

A SPAC (special-purpose acquisition company), sometimes called a blank-check company, is an already-public shell with no operating business that raises money specifically to merge with a private company and take it public. It can be faster and less uncertain than a traditional IPO, which is why SPACs boomed around 2020 and 2021, but the average company that went public via SPAC has a notably weaker track record since, so the route carries its own reputation for hype. The result is the same in each case (a company that trades publicly) but the path, the costs, and the protections differ.

New stocks are some of the most volatile on the market. An IPO can pop on its first day and give back the gain within weeks, or it can fall below its offer price and stay there. Pricing is often driven by enthusiasm and a compelling story rather than steady profits, and many newly public companies are still unprofitable, so the stock can swing hard on each early earnings report. There is also far less history to study: an established company has years of public financials, while an IPO has an S-1 and not much else.

Two specific traps are worth naming. The first is hype: the most heavily marketed debuts can attract buyers at prices that are hard to justify, and the excitement fades. The second is the lock-up expiry. When the 90-to-180-day lock-up ends, insiders and early investors are suddenly free to sell, and a wave of new shares hitting the market can push the price down regardless of how the business is doing. None of this means IPOs are bad, only that a new stock deserves more caution and smaller position sizing than a seasoned one. Walnut is not an investment adviser, so treat these as common patterns, not instructions.

Real debuts make the ideas concrete. 2025 was the strongest year for US IPOs since 2021, with roughly 160 companies raising more than $30 billion. The standout was CoreWeave, an AI cloud infrastructure provider backed by Nvidia, whose stock ran up sharply from its offer price as investors chased AI exposure. Circle, the issuer of the USDC stablecoin, debuted around an $8 billion valuation and rose well beyond it. Figma, the design-software company, was one of the year's biggest offerings, and consumer-finance names like Chime and Klarna also went public. AI, crypto, and cybersecurity listings tended to perform best both at and after their debuts.

The 2026 pipeline is closely watched and includes some of the most valuable private companies in the world, with names like Stripe, Databricks, SpaceX, and frontier AI labs frequently mentioned as potential listings. None of these is a recommendation; they simply show what an IPO looks like in practice, from an unprofitable but fast-growing AI company to a household-name fintech. Figures here are approximate and change quickly; verify current details before deciding anything.

The hard part of an IPO is not the excitement, it is doing the homework: reading the S-1, understanding how the company actually makes money, checking when the lock-up expires, and deciding whether a new, volatile position fits the rest of what you own. Those are specific questions, and an AI assistant can help you work through them, especially when it can also see the portfolio you already hold.

That is where Walnut fits. It connects your existing brokerage through SnapTrade and lets you ask, in plain language through Claude, ChatGPT, or a built-in assistant, how a newly public stock would fit alongside your current holdings, how concentrated you would become, and how a position is doing against the S&P 500 once you own it. It is read-only by default, and you approve any trade. Walnut is not an investment adviser; it helps you see and act on your own portfolio rather than telling you which IPO to buy. If you would rather get broad exposure than bet on a single debut, our best ETF in every category guide covers the low-cost funds that hold hundreds of companies at once.

An IPO is the first time a private company sells shares to the public, turning a privately held business into a stock anyone can trade. Companies do it mainly to raise capital and to give early investors a way to cash out, and the process runs through underwriters, an S-1 filing, a roadshow, a set price, and a lock-up period. Most regular investors cannot buy at the IPO price and instead buy once the stock is trading, which is why chasing a hot debut on day one can be risky.

A traditional IPO is one of three routes to public, alongside direct listings and SPAC mergers, each with different costs and protections. New stocks are volatile, often priced on a story, and prone to dips when lock-ups expire, so they call for caution and small position sizing. Treat the specifics here as a starting point: IPO prices, valuations, and pipelines change fast, so confirm current details before deciding anything.