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Share Dilution Calculator
Model how stock options, warrants, and convertible securities dilute existing shareholders. See the impact on EPS, ownership percentage, and SBC-to-revenue ratio — with live data for any US-listed ticker.
Inputs
Total basic shares — find in the 10-Q cover page
Used to calculate basic vs diluted EPS
New Share Issuance
Stock-based compensation — find in the cash flow statement
Used for SBC-to-revenue ratio
Results
Enter shares outstanding and new issuance to see dilution impact
How to use this dilution calculator
Load a ticker or enter shares manually
Type any US ticker to auto-fill shares outstanding, price, revenue, and net income. Or enter the basic share count from the company's latest 10-Q cover page.
Add dilutive securities
Enter the number of shares from stock options, warrants, and convertible notes. Find these in the equity footnotes of the 10-K or the diluted share count reconciliation.
Check SBC-to-revenue ratio
Enter annual stock-based compensation expense (from the cash flow statement) and total revenue. Below 2% is healthy. Above 5% means SBC is a material drag on per-share economics.
Read the dilution verdict
The results show dilution percentage, diluted EPS vs basic EPS, and color-coded verdicts. Green means minimal impact. Red means the issuance is material — dig into whether the dilution is funding growth or just enriching insiders.
Share dilution explained
Why dilution matters for investors
When a company issues new shares, your slice of the pie gets smaller. If a company has 100M shares and issues 10M more, each original share now represents 0.91% of the company instead of 1%. That's a 9.1% dilution in ownership. More importantly, earnings are now split across more shares — diluted EPS drops even if the business grows.
The question isn't whether dilution happens (it almost always does) — it's whether the value created by the new shares exceeds the value destroyed by the dilution. Issuing shares to fund a high-ROIC acquisition? That's accretive dilution. Issuing shares to cover executive compensation at a company with flat revenue? That's value destruction.
Stock options vs warrants vs convertibles
Stock options give employees the right to buy shares at a set strike price. They dilute when exercised — and the lower the strike vs market price, the more "free" value transfers from existing shareholders to option holders.
Warrants work similarly but are typically issued to investors or lenders as a sweetener. They often have longer terms (5–10 years) and can represent significant latent dilution.
Convertible notes/bonds are debt that converts to equity at a set price. They're deceptively cheap financing — the "interest savings" are paid in future dilution. When conversion triggers, the share count jumps overnight.
SBC: the expense Wall Street ignores
Stock-based compensation is a real cost — it transfers value from shareholders to employees. Yet many analysts add it back to earnings because it's "non-cash." This is misleading: SBC creates new shares that dilute existing owners. If you wouldn't ignore a company paying employees by printing and selling stock on the open market, you shouldn't ignore SBC.
The SBC-to-revenue ratio tells you how expensive the compensation is relative to the business. Below 2% is typical for mature companies. Above 5% is common in high-growth tech but signals that a meaningful portion of revenue is being redirected to employees rather than shareholders. Track the trend — rising SBC/revenue in a decelerating business is a red flag.
How to spot dilution in financial statements
Three places to look: (1) The 10-Q/10-K cover page shows basic shares outstanding — compare this quarter to last year. If it's growing faster than revenue, that's a problem. (2) The equity footnotes list outstanding options, warrants, and convertibles with strike prices and expiration dates. (3) The cash flow statement shows SBC expense — this is the annual cost of equity compensation.
The treasury stock method is how diluted EPS is calculated: only "in-the-money" options (strike below current price) are counted as dilutive. This understates true potential dilution because out-of-the-money options can become in-the-money if the stock rises. For a conservative analysis, count all outstanding dilutive securities.
Frequently asked questions
What is share dilution?
Share dilution occurs when a company issues new shares, increasing the total count and reducing each existing share's percentage of ownership. Common sources include stock options, warrants, convertible bonds, and secondary offerings. Dilution reduces EPS even if total net income stays the same.
How does SBC affect EPS?
Stock-based compensation reduces EPS two ways: it lowers net income (the numerator) as an operating expense, and it increases diluted shares (the denominator) when options and RSUs vest. The combined effect is a double hit to per-share earnings.
What is a good SBC-to-revenue ratio?
Below 2% is healthy for most companies. Between 2–5% is moderate and common in growth-stage tech. Above 5% signals that a material share of revenue is going to stock compensation rather than shareholders — check whether the company is generating enough growth to justify it.
How do I find dilutive securities in a 10-K?
Look in the equity footnotes (usually Note 10–15 in the 10-K). The company must disclose outstanding stock options with weighted average strike prices, warrants, and convertible securities. The diluted EPS footnote in the income statement section also shows the reconciliation from basic to diluted shares.
What is the treasury stock method?
The treasury stock method calculates how many net new shares would be added if all in-the-money options were exercised. It assumes the company uses exercise proceeds to buy back shares at the current market price. Only the net incremental shares are added to the diluted count.
Is dilution always bad?
No. Dilution is bad when it enriches insiders without creating shareholder value. But issuing shares to fund high-return acquisitions, invest in growth with strong unit economics, or retain exceptional talent can be accretive — the value created exceeds the dilution cost. Judge dilution by what the shares bought, not just the dilution itself.