What is an IPO

For most investors, an IPO begins when a company's shares start trading on a stock exchange.

In reality, that's the final step.

By the time the opening bell rings, investment banks have already spent weeks meeting with investors, assessing demand, and determining how shares will be distributed. The offering price has been set, most allocations have already been made, and the company is about to begin life as a public business.

Going from private to public

An initial public offering, or IPO, is the process through which a private company becomes publicly traded.

Companies go public for different reasons. Raising capital is often the primary objective, but an IPO can also increase visibility, broaden ownership, and create liquidity for existing shareholders over time.

Going public also introduces new responsibilities. Public companies are expected to meet ongoing reporting and disclosure requirements and operate within the rules of the exchange where they're listed.

Before trading begins

Long before investors see a company's ticker symbol on an exchange, the IPO process is already underway.

The company appoints one or more investment banks to act as underwriters. Their role extends beyond listing the shares. They help prepare the offering, work with the company on valuation, introduce the business to prospective investors, and manage the distribution of shares.

As interest builds, underwriters begin collecting non-binding indications of interest from investors. This process, known as book-building, helps determine both the final offering price and how the available shares will be allocated.

Why don't all investors receive shares?

Submitting interest in an IPO isn't the same as buying shares.

When demand exceeds the number of shares available—as it often does in high-profile offerings—underwriters decide how those shares will be distributed. Some investors receive their full allocation, others receive fewer shares than requested, and some receive none at all.

This isn't unique to retail investors. Institutional allocations are adjusted as well. The difference is that institutions participate directly in book-building and account for most of the demand collected during the offering.

A process built over decades

The way IPOs work today reflects decades of market development.

The objective has always been the same: help companies raise capital efficiently while giving investors confidence that newly listed shares will trade in an orderly market. The mechanics of modern IPOs—from book-building to allocation—evolved around those goals.

While access has broadened over time, the underlying process has changed remarkably little.