What this calculator does
This page is not affiliated with, endorsed by or connected to Anthropic. It is a general calculator for working out what money put into a share at a known price is worth after the price moves, and it carries no information about any company's offering. Nothing here is investment advice or a prediction, and no price is filled in for you, because an offer price does not exist until a company and its underwriters set one at pricing.
What it does add over a plain return calculation is the part specific to a public offering. You apply for an amount and may receive a fraction of it. You can only hold whole shares. And you pay brokerage at both ends. Together those three things mean the money you get back is never quite the headline percentage, and on a small allocation it is not close.
The formula
The amount you apply for is scaled by the share of your application that is filled, and that figure is divided by the price to give whole shares, rounding down. What is left over stays as cash. The shares are then revalued at price × (1 + change) and brokerage is subtracted at both the buy and the sell, so the return is measured against what you actually spent rather than against what you offered.
| Term | Meaning |
|---|---|
| Offer price | The price the company and its underwriters set for the offering. It is decided at pricing, not before. |
| Allocation | The share of your application you actually receive. In a heavily oversubscribed deal it can be a small fraction, and the rest of your money comes back. |
| First traded price | The price when the shares begin trading, which can be well above or below the offer price. It is usually the first price a retail buyer can actually pay. |
| Break-even price | The share price at which you get your money back after brokerage at both ends. |
The inputs explained
| Field | What to enter |
|---|---|
| Amount you want to invest ($) | The amount you are putting in. If you are applying in an offering, this is what you apply for rather than what you will necessarily receive. |
| Price per share you pay ($) | The price per share you actually pay. Use the offer price only if you expect an allocation at that price; if you plan to buy once trading starts, use the price you expect to pay then, which is a different and usually higher number. |
| Price change after that (%) | The percentage move from the price you paid. Enter a negative figure for a fall. This is your own assumption and the calculator makes no claim about it. |
| Share of your application filled (%) | The share of your application you receive. Leave it at 100% if you are simply buying on the market, where you get what you order. |
| Brokerage per trade ($) | Brokerage per trade, charged once on the way in and once on the way out. |
When to use it
Buying on the market rather than in the offering
Set the allocation to 100% and use the price you can actually buy at. Most people who want shares in a newly listed company buy them after trading starts, not in the offering, and the price then is whatever the market has decided rather than the offer price.
Applying into an oversubscribed offering
Lower the allocation. At 30% of a $5,000 application you end up with $1,500 of shares and $3,500 back in your account, so a 25% rise is worth $355 rather than $1,230. The percentage return slips too, from 24.6 to 23.5, because the flat brokerage is spread over a smaller position.
Checking what a flat result costs you
Set the change to zero. You are down by exactly the two brokerage charges, which is the floor on any trade. The break-even output gives the price that cancels them out.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
What does a price move do to a $5,000 investment?
Only the price move changes.
| Price change | Value of your shares | Profit or loss after fees | Return on what you invested |
|---|---|---|---|
| -100% | $0.00 | −$5,020.00 | -100.2% |
| -50% | $2,500.00 | −$2,520.00 | -50.3% |
| -25% | $3,750.00 | −$1,270.00 | -25.3% |
| 0% | $5,000.00 | −$20.00 | -0.399% |
| +25% | $6,250.00 | $1,230.00 | 24.6% |
| +50% | $7,500.00 | $2,480.00 | 49.5% |
| +100% | $10,000.00 | $4,980.00 | 99.4% |
| +200% | $15,000.00 | $9,980.00 | 199.2% |
What does a small allocation do?
The money applied for is the same in every row. Only the share of it filled changes.
| Application filled | Shares you hold | Profit or loss after fees | Return on what you invested | Cash left uninvested |
|---|---|---|---|---|
| 5% | 5 | $42.50 | 16.3% | $4,750.00 |
| 10% | 10 | $105.00 | 20.6% | $4,500.00 |
| 25% | 25 | $292.50 | 23.2% | $3,750.00 |
| 50% | 50 | $605.00 | 24.1% | $2,500.00 |
| 100% | 100 | $1,230.00 | 24.6% | $0.00 |
Questions
Is this page connected to Anthropic?
No. It is not affiliated with, endorsed by or connected to Anthropic, and it contains no company information. It is a general IPO return calculator and every figure in it is one you enter.
Why is there no price filled in?
Because an offer price does not exist until a company and its underwriters set one at pricing, and this site does not publish figures that would go stale. Enter the price you would actually pay.
Can I buy at the offer price?
Usually not. Offer-price allocations mostly go to institutions and to brokerage clients who meet specific conditions. Most private investors buy once trading starts, at whatever price the market sets, which may be a long way from the offer price in either direction.
Why is my return less than the price move?
Brokerage at both ends, and whole shares. A 25 per cent rise on $5,000 at $50 a share returns 24.6 per cent once $20 of fees is taken out, and if the price does not divide evenly into your money the remainder sits as cash and earns nothing.
Is this investment advice?
No. It is arithmetic on figures you supply. It does not know or predict any share price, it cannot tell you whether an investment is suitable for you, and a newly listed share can fall as easily as it can rise. For advice on your own circumstances, speak to someone licensed to give it.
What is Anthropic’s listing status?
Anthropic said it had confidentially submitted a draft registration statement on Form S-1 to the US Securities and Exchange Commission on 1 June 2026. Anything beyond that, including whether an offering happens at all, is for the company and the regulator to confirm rather than this page.
For the plain return on any investment there is return on investment, and holding period return handles a share bought and sold with dividends along the way. To average several purchases at different prices, see average share cost and position, and for growth over several years CAGR.