Calculator
Total diluted shares before the offering. From the 10-Q cover page or earnings release.
The undisturbed price before the offering announcement.
Number of new primary shares being issued. Primary shares only — exclude secondary (insider) shares.
Price at which new shares are being sold. Typically 3–8% below current price.
Bank underwriting fee as % of gross proceeds. Typically 4–7%. Leave blank to use gross proceeds.
Overallotment as % of offering size (typically 15%). Enter 0 if no greenshoe. Shows max-dilution scenario if exercised.
Ownership dilution
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New shares as % of post-offering total
Offering discount
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Offering price vs. current price
Gross proceeds
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Before underwriting fees
Net proceeds to company
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After underwriting discount
Theoretical post-offering price
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If cash held at par (pre-deployment)
Per-share value impact
Theoretical price vs. current price
If greenshoe is fully exercised
Max ownership dilution
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Base offering + greenshoe
Max gross proceeds
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With greenshoe exercised
Post-offering price (max dilution)
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Theoretical with full greenshoe
How to Use This Calculator
Enter the company's current shares outstanding (in millions) from the most recent 10-Q or earnings release cover page. Enter the current share price — use the undisturbed price before any offering announcement or rumor for the most accurate discount calculation. Enter the number of new primary shares being offered (in millions) — this should be the new share issuance only, not any secondary shares that insiders may be selling simultaneously, as secondary sales do not increase share count.
The offering price is what new investors pay per share. It is typically set 3–8% below the pre-announcement close to attract institutional buyers who commit to large blocks. The underwriting discount is the bank's fee — typically 4–7% of gross proceeds — deducted from what the company actually receives. Net proceeds (gross proceeds minus underwriting fees) are what the company receives and will deploy.
The greenshoe field is optional. Enter the overallotment option percentage (standard is 15% of the base offering size) to see the maximum dilution scenario if the greenshoe is fully exercised. The greenshoe shows how many additional shares the underwriter can deliver to meet excess demand. The results section shows both the base scenario and the fully-exercised greenshoe scenario side by side.
Understanding the Outputs
The ownership dilution percentage is the most commonly cited headline number — it is the new shares issued as a fraction of total post-offering shares outstanding. A 10 million share offering into 100 million existing shares produces 10M / 110M = 9.09% ownership dilution. Every existing shareholder now owns 90.91 cents of the company for every dollar they owned before. This is the share count impact.
The theoretical post-offering price is calculated as: (pre-offering market cap + net proceeds) / post-offering share count. This represents the fair value per share assuming the company holds all proceeds as cash with no immediate return on investment. If the offering price is close to the current price, the theoretical post-offering price is close to the current price — the dilution in intrinsic value is small because the company received approximately fair value for the new shares. If the offering price is at a deep discount (say, 20% below current price), the theoretical post-offering price is meaningfully below the current price, reflecting real value transferred to new investors.
The per-share value impact is the difference between the theoretical post-offering price and the current share price — expressed as a dollar amount and a percentage. This is the true intrinsic value dilution per existing share, which is typically smaller in magnitude than the ownership dilution percentage when offerings occur near market price. The market's actual price reaction on announcement day typically matches this theoretical impact as a starting point, then diverges based on how investors interpret the signal embedded in the offering (growth capital vs. distress).
The gross vs. net proceeds distinction matters for modeling the company's post-offering financial position. The cash that actually enters the company's balance sheet is net proceeds — gross minus underwriting fees. A $500 million gross offering with a 5% underwriting discount delivers $475 million to the company. Analysts modeling the company's pro-forma cash position and financial ratios should use net proceeds, not gross.
Assumptions and Limitations
- Primary shares only: This calculator models primary share issuances that increase the total share count. Secondary sales by insiders do not increase share count and should not be entered as new shares. If a deal is mixed (primary + secondary), enter only the primary component for the dilution calculation.
- Cash held at par: The theoretical post-offering price assumes net proceeds are added to the company's equity value as cash — no immediate return on investment from deployment. If the proceeds are deployed immediately to high-return investments, the theoretical post-offering price understates the true fair value per share post-offering.
- No adjustment for other dilutive securities: The calculator uses simple shares outstanding, not fully diluted share count including options, warrants, convertibles, and RSUs. For a company with significant equity compensation overhang, the true fully diluted post-offering share count may be higher than shown here.
- Pre-deployment snapshot: The theoretical price is a snapshot at offering date, before the company deploys the capital. Return on deployed capital over the following 1–3 years is the dominant driver of actual share price performance, and is not modeled here.
- Greenshoe assumption: The greenshoe results assume the overallotment option is fully exercised. In practice, partial exercise is common depending on whether the stock trades above or below the offering price in the 30 days post-offering.
Frequently Asked Questions
Why is the true per-share dilution smaller than the headline ownership dilution?
Ownership dilution (new shares / total new shares) measures how much your percentage stake in the company decreases. Per-share intrinsic value dilution measures how much the value behind each share changes. When the company sells new shares at or near fair value, it receives close to fair value in cash — which immediately offsets most of the ownership dilution on a per-share basis. The "give-away" to new investors is only the discount below fair value, not the full amount raised. A 10% headline dilution at a 5% discount to current price produces far less than 10% intrinsic value dilution per share.
Why do stocks often fall more than the theoretical dilution suggests?
Several factors cause the actual market reaction to exceed the theoretical dilution: (1) the offering reveals information — if the company needs equity capital, investors may revise down their estimates of future earnings or cash flows; (2) short-term supply pressure from traders who short the stock into the offering (a common institutional practice to hedge participation); (3) uncertainty about how proceeds will be deployed; (4) general negative sentiment signaling from seeing insiders willing to issue equity at current prices. The theoretical post-offering price is a floor if the offering is value-neutral; the actual market reaction reflects all of these factors simultaneously.
What is "double dilution" and when does it occur?
Double dilution occurs when a company has both: (1) existing dilutive securities (options, warrants, convertibles) that are in-the-money and will eventually convert to shares, and (2) a new primary share offering. The base diluted share count already includes the conversion of in-the-money securities under the treasury stock method. An additional primary offering on top of that further dilutes an already-diluted count. The fully diluted post-offering share count is higher than what a simple outstanding-shares-plus-new-shares calculation shows. Companies with large option or convertible overhangs should be modeled using the fully diluted count as the starting point, not the basic outstanding count.
How do I find current shares outstanding for a public company?
Basic shares outstanding are on the cover page of the most recent 10-Q or 10-K (the sentence beginning "As of [date], there were [X] shares of common stock outstanding"). Diluted shares (including options, RSUs, convertibles) are in the Earnings Per Share footnote in the financial statements. For the most current number, many companies also report shares outstanding in their earnings press release. For real-time intraday data, check the company's investor relations page or financial data providers. Note that shares outstanding fluctuates as RSUs vest, options are exercised, and buybacks are executed.
Does this calculator work for PIPE transactions?
A PIPE (Private Investment in Public Equity) is a private placement of new shares to selected institutional investors, typically at a discount to market price. The dilution mechanics are identical to a public offering: new shares issued at a discount increase the share count and dilute existing holders. The key differences from a public offering are: PIPE shares may be restricted (not freely tradable until SEC registration), the discount is often larger (10–20% vs. 3–8%), and PIPEs can close much faster than public offerings (days rather than weeks). The calculator's inputs and outputs apply equally to PIPE transactions — enter the PIPE size, price, and underwriting cost (often zero for PIPEs placed without a bank) in the same fields.
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Disclaimer
This calculator is for educational purposes only and does not constitute investment advice. Dilution calculations are mechanical estimates based on the inputs you provide and do not account for the return on capital deployed, business quality, or market sentiment. Actual post-offering stock prices depend on many factors not modeled here. Consult a qualified financial professional before making investment decisions.