ETF Combiner

What this tells you

An ETF (exchange-traded fund) is a basket of many investments that you buy as one share. This tool opens the basket: type a fund's ticker, such as QQQ, and it lists every holding inside at its weight, meaning its share of the fund's money. Type several funds, with how much of each you want, and it adds them together into one basket: the list of stocks you would buy to own that mix directly.

If you enter an amount, it splits that amount across the basket to the cent and, for the 40 largest US stocks, works out roughly how many shares that is at the last closing price.

It starts with an example mix, a quarter each of VDC, QQQ, VNQ and Berkshire Hathaway's stock portfolio. Clear all empties it so you can build your own from scratch. Hover over a holding's weight to see how much of the basket it and every larger holding make up together.

Leaving out the smallest holdings

A broad fund can hold hundreds or thousands of companies, many of them tiny slivers. Buying every one yourself is impractical. Set Leave out holdings under to a percentage, such as 0.5%, and every holding smaller than that share of the basket is dropped.

The holdings that remain are then scaled up so they add to 100% again, and they keep their sizes relative to one another. For example, if a basket is 45% of one stock, 25% of another, 15% of a third and two 7.5% holdings, a 10% cutoff drops the two 7.5% holdings (15% in total). The other three are each divided by 0.85, so they become about 52.9%, 29.4% and 17.6%. The first is still exactly 1.8 times the second, as it was before.

The cutoff is compared with each holding's weight in the combined basket, before anything is removed. A company held by two of your funds counts once, with both parts added together.

Taking out holdings you don't want

Every row of the basket has a Remove button. A holding you remove moves to a list under the basket, where Put back returns it. Turn on Only holdings on a US exchange to take out every stock that trades only abroad, such as Samsung in Korea, or a foreign company whose only US trading is "over the counter", outside the stock exchanges. Bonds stay in.

If your mix holds real estate investment trusts (REITs, companies that own buildings and collect rent), a Real estate sectors box lists each kind of property they own (apartments, health care, offices, self storage and so on) with a checkbox. Uncheck a sector to take out every REIT in it. For example, with REZ you could keep the apartment and health care landlords and drop self storage. The sectors come from the list of REITs in the Vanguard Real Estate ETF (VNQ); a REIT that VNQ doesn't own has no sector and always stays in.

Whatever you take out, the rest are scaled up together, by the same factor, so they still add to 100% and keep their sizes relative to one another. Each rule looks at the basket before anything was taken out, so removing one stock never pushes another over or under the cutoff.

Holding companies like Berkshire Hathaway

Some companies' main business is owning other companies. For Berkshire Hathaway (BRK.B or BRK.A), Markel, Loews, Fairfax Financial and Daily Journal you can choose, for each one, between:

• Its reported stock portfolio. Large investors must tell the SEC which US-listed stocks they own every three months, on a form called 13F. This uses the latest one, weighted by the value of each stake.
• Its shares themselves. The basket simply holds the company's own stock.

The two are not the same. A 13F only covers US-listed stocks, so it leaves out the businesses these companies own outright (Berkshire owns BNSF railway and GEICO, for example), their cash and bonds, and stakes in companies listed abroad. It is published up to 45 days after the quarter ends, and a new stake can be kept confidential for a while. Copying the 13F copies the stock portfolio, not the company.

What it does not include

• Cash and derivatives. Funds keep some cash and some hold futures or swaps. Those are left out, and each fund's remaining holdings are scaled to 100%. A fund that gets most of its returns from derivatives (leveraged, inverse or option-income funds) is flagged, because its stocks alone do not behave like the fund.
• Today's exact holdings. Most funds' complete holdings come from a filing with the SEC called Form N-PORT, which becomes public about 60 days after the date it describes. Each fund shows its date. SPY, DIA and MDY publish daily instead.
• Costs and taxes. Trading fees, taxes, and the fund's own fee are not counted.
• Keeping it up to date. A basket you buy yourself drifts as prices move, while the fund rebalances on its own. Leaving out small holdings also makes your basket differ a little more from the fund.

Things worth knowing

Weight is a holding's share of the basket's total value. Bonds have no ticker; they are bought through a broker's bond desk, usually in $1,000 amounts. Holdings outside the US trade on foreign exchanges and need a broker with access to them.

Your mix, cutoff and amount stay in your browser. The site only asks its server for each fund's public holdings by ticker, and for closing prices by ticker.

Common questions

Why do the weights not match the fund's own website?

Funds report weights including cash, and the website may be a newer day than the latest filing. Here cash is left out and the rest scaled to 100%, so each weight is a little higher.

Will leaving out small holdings change my returns?

Slightly. The basket then leans a little more on the larger companies. The table and the "Left out" figure show exactly how much of the basket was dropped.

Does it remember my mix when I reload?

No. Nothing you type is saved. Use Download CSV to keep a copy of the basket.