Your portfolio spreadsheet knows what funds you own. It doesn't know what's inside them.
Published 2026-10-02
If you keep your investments in a spreadsheet, you are not doing anything wrong. A sheet is a good tool for this. You choose the columns, you own the data, and nothing is hidden from you.
It is good at three things: adding up balances across accounts, showing your split between asset classes, and tracking what you contributed. If that is all you need, you may not need anything else.
This page is about the one question a sheet cannot answer, and why.
What a sheet does well
Here is a layout that works, with one row per holding:
| Column | What goes in it |
|---|---|
| Account | Taxable, Traditional IRA, Roth IRA, old 401(k) |
| Holding | The fund or stock name |
| Ticker | As listed |
| Shares | From your statement |
| Price | From a price function or typed in |
| Value | Shares × Price |
| Expense ratio | From the fund's own page, or your 401(k) fee disclosure |
| Yearly fee | Value × Expense ratio |
Add a total row and a pivot by account and you have your whole picture. The Yearly fee column also gets you your fee in dollars per year, which most statements never show. Our fees walkthrough covers that calculation.
Where the price column stops helping
Spreadsheet price functions return quotes. Google's documentation for its
GOOGLEFINANCE function lists attributes such as price, volume, market cap, 52-week
high and low, and P/E, and says quotes can be delayed by up to 20 minutes. For mutual funds it
says, in its own words, that fund attributes are "currently not supported in Google Sheets."
Notice what is not on that list: what a fund owns. There is no attribute for "the companies inside this fund, and how much of each", and none for a fund's expense ratio either. The sheet can know a fund's name and, for many tickers, its price. It does not know its contents.
Why that matters: the same company, three times
Say you hold three funds, one in each of three accounts. Everything below is hypothetical.
| Account | Fund (hypothetical) | Balance |
|---|---|---|
| Taxable brokerage | Fund A, total U.S. market index | $90,000 |
| Roth IRA | Fund B, large-cap growth | $40,000 |
| Old employer 401(k) | Fund C, target-date 2045 | $70,000 |
Your sheet shows three funds in three different categories, which looks like spread-out money. Suppose that one large company makes up 6% of Fund A, 11% of Fund B, and 4% of Fund C. The amount you hold in that one company, through all three, is:
- Fund A: $90,000 × 6% = $5,400
- Fund B: $40,000 × 11% = $4,400
- Fund C: $70,000 × 4% = $2,800
- Total: $12,600, or 6.3% of your $200,000
No single row in your sheet shows $12,600. It is spread across three rows in three accounts, and each fund page shows only its own percentage. That is the thing a spreadsheet misses: the total only exists once you look through every fund at once.
What it takes to do this by hand
You can do it, and some people do. The steps:
- For each fund, find its full list of holdings. U.S. mutual funds and ETFs report holdings to the SEC. The public release of a fund's quarter-end holdings comes roughly 60 days after the quarter ends, so the file you find can be a couple of months old.
- Pull each fund's holdings into its own tab. A broad index fund can hold hundreds or thousands of lines.
- Match company names across tabs. The same company can appear under slightly different names, share classes or identifiers, so a plain lookup misses some.
- For each company, multiply each fund's percentage by your dollars in that fund, and add across funds.
- Do it again when the filings update, and every time you buy or sell.
That is not a formula you write once. It is a recurring chore, and it grows with every fund you add. This is the line where a spreadsheet stops being the right tool. It is not that the sheet is bad. It is that the data this question needs does not live in the sheet.
A faster way to see your own number
Our fund overlap calculator takes two to five fund tickers and a portfolio value. It shows how much of what the funds hold is shared, and your largest single-company exposure through them. There is no account and nothing is saved.
Two limits to know about. It splits your value equally across the tickers you enter, so it is an illustration unless your balances are roughly equal. And it covers the funds you type in, not your whole picture.
What a result means, and what it doesn't
A high overlap number means your funds hold many of the same companies. It does not mean you should change anything. That depends on your taxes, which accounts the funds sit in, what your plan menu offers, and your own goals. We show you what you hold. We don't tell you what to hold.
Datum shows you what you own. It does not give investment advice or recommend what to buy or sell.