What's an example of a capped fund?
The S&P runs a capped fund in each of the 11 sectors that it classifies the stock market into.
One of them is the S&P Select Sector Capped 20% Technology Index. In this case, the cap is a reference to the weighting within the fund. No stock can have a weight of more than 19%.
This kind of cap can be useful in a sector where there are several stocks trading in the trillion-dollar market cap range, like technology, or where a handful dominate the industry.
Generally speaking, a capped fund is likely to be a better fit for an investor who wants to avoid being surprised by fees, and for one who wants a guarantee that the fund will remain diversified.