How to Create a What-If Stock Portfolio With Percentages

A percentage allocation is easier to compare than a list of dollar amounts. It tells you what role each position has in the mix and makes the result independent of the account size.

In Equity Replay, the goal is not to find a perfect allocation. The goal is to make one clear enough to replay, edit, and explain.

1. Start with a specific idea

Choose a question for the replay. You might want to compare a concentrated group of companies, recreate a public disclosure snapshot, or see how an equal-weight mix differs from a more concentrated one.

Avoid starting with a vague list of “good stocks.” A clear idea produces a clearer result.

2. Add the positions

Use the stock search to add the companies you want to include. Give each one a weight. For example:

• AAPL — 35%
• MSFT — 30%
• AMZN — 20%
• GOOGL — 15%

This mix totals 100%, so it is ready for a historical replay. The percentages are the only thing that determines each position’s influence; share price does not.

3. Choose the historical window

Use one month or six months when you want a compact comparison. Use five or ten years when you want a longer historical context. A longer window is not automatically a better answer—it is a different question with a different start date.

4. Read the result, then edit one thing

Look at the estimated value, historical change, chart path, and contribution breakdown together. Then change one weight and update the estimate. Small edits make it easier to see how concentration changes the result.

Equity Replay applies the allocation once at the starting point. There are no interim trades, deposits, withdrawals, or rebalancing assumptions. The result is an illustrative historical view, not a recommendation or a record of an account.

For the exact calculation, read how Equity Replay calculates a historical portfolio replay. When you are ready, create your own portfolio.