But with some exceptions, you will mostly own stocks in integer amounts. You own one share or zero. That doesn’t give you $13.30 of WMT, that gives you $96.98 of WMT or $0.00 of WMT. Index funds work because the funds are large enough—a fund with $10 million in assets can buy 1,371 shares of WMT at $96.98 for $132,959.58 which is close enough. And then the index fund has to periodically rebalance—the share price of WMT changes, the weighting of WMT in the S&P500 changes, and the fund then has to buy or sell shares of WMT.

You could come up with a way to do something like having your own index fund, but it would involve partial ownership of shares, and pooling your assets with people who disagree with you about the way to allocate assets, which makes things more complicated and probably more expensive.

My personal take on this is that these more complicated schemes can often end with retail traders getting the short end of the stick. That’s why low-fee ETFs have been so successful.

I think if you want a weighting other than what the index fund gives you, then there are ways to do that—maybe these involve some fees, but c’est la vie. You can buy “tilted” ETFs, you can buy exposure to specific stocks or funds, you can hedge exposure to specific stocks or funds. But you are probably going to have a hard time making your own basket with a lot of stocks in it. Retail trading just does not get access to the same strategies that wall street has.

That’s a spread. Everything has a spread.