iShares Semiconductor ETF (SOXX)

This is the most concentrated, fast-moving holding in many people's portfolios, with price swings roughly twice the broader market's.

What is going on right now?

It dropped close to 8% in a single week, and a lot more shares changed hands than usual during that slide.

How is the business itself doing?

This is a basket of U.S. chip companies, nothing else. Its five largest names, including Nvidia, Broadcom, and AMD, make up about two-fifths of the whole thing, so a rough patch for any one of them shows up fast.

What stands out?

It costs about a third of what similar funds charge, at 0.33% a year, and it manages over $48 billion. But it holds only one slice of the economy, so when chips cool off, there is nowhere inside it to hide.

What comes next?

Bank of America estimates roughly $2.1 trillion in data-center spending by 2028, and chip companies are a direct supplier to that buildout.