What Happens When a Company Goes Public: Stock, Taxes, and Governance

When a company goes public, it sells shares to outside investors for the first time through a registered offering, raising cash that lands on its balance sheet and permanently changing how the business is owned, governed, and monitored. The offering itself usually takes six to nine months from the decision to file. On the other side, the company answers to public shareholders, files continuous disclosures with the SEC, and operates under listing standards set by whichever exchange it joins. Existing owners see their ownership percentages shrink, but the shares they still hold become tradable on a public market.

How the Offering Itself Works

The company hires investment banks as underwriters. A lead bank assembles a syndicate to spread the shares across institutional and retail investors, since a concentrated shareholder base on day one tends to trade violently.

The formal regulatory step is filing a registration statement on Form S-1 with the Securities and Exchange Commission.¹ The S-1 lays out the business model, financial history, management team, risk factors, and planned use of proceeds. Until the SEC declares the filing effective, the Securities Act of 1933 restricts what the company can say publicly about the offering. This is the “quiet period,” and it exists to keep hype from distorting investor demand before the disclosures are complete.

While the filing is pending, senior executives run a roadshow, pitching institutional investors in major financial centers while the underwriters collect non-binding indications of interest. Those meetings shape the price range. The underwriters then run a book-building process to tally demand at various prices and set the final offering price the evening before trading begins.

The company sells its shares to the underwriters at a discount to that offering price, and the gap is the underwriting fee. For most midsize IPOs raising under roughly $200 million, the fee is a flat 7% of proceeds.² Larger deals negotiate lower rates, with offerings above $1 billion typically in the 4% to 5% range. Legal, accounting, and filing costs push total IPO expenses well above 10% of proceeds on many deals.³

Underwriters usually receive a greenshoe option, letting them sell up to 15% more shares than originally planned if demand is strong. It also functions as price stabilization: the syndicate initially oversells the offering to create a short position. If the stock drops after day one, the banks buy in the open market to cover, putting a floor under the price. If the stock rises, they cover the short with newly issued shares at the offering price by exercising the greenshoe.

Once the stock begins trading on the NYSE or Nasdaq, the company is public. The opening price is set by market supply and demand and may differ substantially from the offering price.

Dilution of Existing Ownership

Any IPO that issues new shares dilutes existing owners. A company with 80 million shares outstanding that sells 20 million new shares to the public moves its original owners from 100% of the company to 80%. Their share count is unchanged; each share simply represents a smaller slice.

The offsetting logic is that the company’s total value should rise by roughly the cash raised. A $4 billion pre-money company that raises $1 billion is worth $5 billion afterward, so per-share value holds even as ownership percentages fall. In practice, the market price after the IPO depends on investor sentiment and can diverge from that math.

Governance Changes After Listing

Listing forces a restructuring of how the company is run. The board, which may have been a small circle of founders and early investors, has to meet the standards of the exchange the company joins. Both the NYSE and Nasdaq require a majority of directors to be independent, meaning no material financial or personal ties to the company or its management.⁴

Independent directors have to staff the committees that check management. Under Nasdaq rules, the audit committee needs at least three members who are all independent, able to read and understand financial statements, and at least one of whom qualifies as a financial expert based on relevant professional experience.⁵ The compensation and nominating committees carry similar independence requirements. These committees hold real authority over the outside auditor relationship, executive pay, and who is put forward as a director candidate.

Sarbanes-Oxley Certifications

Sarbanes-Oxley adds direct accountability at the top. Section 404 requires management to assess the effectiveness of the company’s internal controls over financial reporting annually and include that assessment in the annual report.⁶ For larger companies, an independent auditor must also sign off on that assessment. Section 302 requires the CEO and CFO to personally certify the accuracy of every quarterly and annual filing, attesting that the financials fairly present the company’s condition and that they have evaluated the internal controls. False certifications create personal liability for the officers.

Shareholder Voting

Public shareholders elect directors, approve major transactions like mergers, and vote on equity compensation plans. Most participate through proxy ballots submitted before the annual meeting, and the company must distribute a detailed proxy statement disclosing candidates, executive pay, and every proposal.

Under the Dodd-Frank Act, public companies must hold a non-binding advisory vote on executive compensation, commonly called “say-on-pay.” The vote does not force changes, but a company that consistently loses it faces pressure from institutional investors and proxy advisory firms to restructure pay practices.⁷

Shareholders can also put items on the ballot themselves. Under SEC Rule 14a-8, a shareholder who has held at least $25,000 in company stock for one year, $15,000 for two years, or $2,000 for three years can submit a proposal for inclusion in the proxy statement.⁸ These proposals are advisory but create public accountability on issues like environmental policy, political spending, and board composition.

Ongoing SEC Reporting

Public companies live under continuous disclosure. Regulation Fair Disclosure prohibits selectively sharing material nonpublic information with favored analysts or large shareholders. If an executive accidentally discloses something material in a private conversation, the company must publicly release that information promptly.⁹

On top of that baseline, the SEC mandates a fixed reporting schedule:

Form 10-K, the annual report, filed after each fiscal year-end with full audited financial statements, management’s discussion and analysis, a business description, and a comprehensive list of risk factors.¹⁰
Form 10-Q, the quarterly report, filed after each of the first three fiscal quarters with reviewed (not fully audited) financials and updated management analysis.¹¹
Form 8-K, the current report, filed within four business days of a significant unscheduled event such as a change in CEO, a major acquisition, or a bankruptcy filing.¹²

An independent auditing firm reviews the annual financials and issues an opinion on compliance with Generally Accepted Accounting Principles. Between external auditors, internal compliance staff, legal counsel, and the technology systems needed to support internal controls, compliance spending can run into the millions of dollars annually even for smaller public companies.⁶

What Changes for Founders, Employees, and Early Investors

For people who held equity before the IPO, the offering converts paper wealth into something they can eventually spend. Eventually, not immediately. Nearly all pre-IPO shareholders sign lock-up agreements barring them from selling for a set period after the offering, most commonly 180 days.¹³ The lock-up prevents a wave of insider selling from cratering the stock right after debut. When it expires, the increase in shares available to sell often pushes the price down.

Even after the lock-up lifts, insiders face permanent restrictions. Section 16 of the Securities Exchange Act requires officers, directors, and anyone owning more than 10% of the company’s stock to report their holdings and every transaction to the SEC on Forms 3, 4, and 5.¹⁴ Form 4, which reports changes in ownership, must be filed within two business days of a trade. Every insider purchase and sale is visible to the market in near real time.

Insiders and holders of restricted stock also have to comply with Rule 144 when selling. Rule 144 sets conditions on holding periods, volume limits, and manner of sale so that large insider dispositions don’t function as a disguised secondary offering.¹⁵ Most companies layer on their own trading policies too, including blackout periods around quarterly earnings when insiders cannot trade at all.

Civil penalties for insider trading can reach three times the profit gained or loss avoided from the illegal trade.¹⁶ Criminal prosecutions carry potential prison time.

For employees below the executive tier, the IPO converts illiquid stock options or restricted stock units into publicly tradable equity, subject to the same lock-up and to the tax treatment described next.

Taxes on Pre-IPO Equity

The tax consequences depend on the type of equity held, when it was acquired, and when it is sold.

Restricted Stock Units

RSUs are the most straightforward. You owe ordinary income tax on the full fair market value of the shares when they vest and are delivered to you. If your RSUs vest on a day the stock trades at $40 per share and you receive 1,000 shares, that is $40,000 of ordinary income for the year. The employer withholds taxes at vesting. Any gain above $40 per share when you later sell is taxed as a capital gain, with the rate depending on how long you held after vesting.

Incentive Stock Options and the AMT Trap

Incentive stock options carry a tax advantage with a trap attached. Exercise your ISOs and hold the resulting shares for at least one year after exercise and two years after the grant date, and the entire profit on sale is taxed as a long-term capital gain. That is a much lower rate than ordinary income. The trap: when you exercise ISOs, the spread between the exercise price and the fair market value at exercise counts as income for alternative minimum tax purposes, even though you have not sold anything and have no cash in hand. Around an IPO, when the stock may be at a peak, the AMT liability from a large ISO exercise can be enormous.

Nonqualified Stock Options

NSOs are simpler and less tax-advantaged. You owe ordinary income tax on the spread between the exercise price and the market price at exercise, and that income is subject to payroll tax withholding. Any additional gain when you eventually sell is a capital gain.

Qualified Small Business Stock

Founders and very early investors may qualify for a substantial exclusion under Section 1202 of the Internal Revenue Code. If the company was a qualifying C corporation with aggregate gross assets of $75 million or less when the stock was issued, and the shareholder holds the stock for at least five years, up to 100% of the gain on sale can be excluded from federal income tax. The maximum excluded gain is the greater of $15 million or ten times the shareholder’s adjusted basis in the stock, for shares acquired after July 4, 2025. Shorter holds offer partial exclusions: 50% after three years and 75% after four years.¹⁷ For stock acquired before that date, the per-issuer limit is $10 million and the full exclusion requires a five-year hold with no partial tiers. The $15 million figure begins adjusting for inflation in 2027.

Section 1202 applies at the federal level. Some states conform to it and some do not, which affects the net savings.

Direct Listings and SPACs

An underwritten IPO is not the only route to a public listing, though the destination is the same regulatory regime.

In a direct listing, the company skips the underwriters. No new shares are issued, no capital is raised for the company, and there is no lock-up period. Existing shareholders sell their own shares directly to the public once trading opens on an exchange.¹⁸ The opening price comes from buy and sell orders matched that morning rather than from underwriter book-building the night before. The trade-offs: no underwriting fees, no dilution from new shares, and no forced holding window, but also no price stabilization, no greenshoe, and no guaranteed pool of institutional buyers on day one.

A special purpose acquisition company is a shell that goes public first, raises cash through its own IPO, and then merges with a private company within roughly two years.¹⁸ The private company becomes public through this “de-SPAC” merger rather than through its own IPO. The pitch is a faster timeline, more certainty on valuation, and the ability to make forward-looking financial projections that traditional IPO rules restrict. The costs are dilution from the sponsor’s promote (often 20% of shares) and from warrants issued to the SPAC’s IPO investors, and tighter SEC disclosure requirements have narrowed the regulatory gap that once made SPACs attractive.

Whichever path a company takes, once it is public, the SEC reporting, governance requirements, and insider trading rules apply the same way.

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