The Russell 2000 Index has traditionally been home to U.S. small-cap stocks—that is, smaller and often lesser-known companies. Its largest constituents share one common trait: the construction and operation of data centers for artificial intelligence. Each of these companies, however, benefits from a different part of the same supply chain. One company supplies power, another provides data connectivity, and a third builds the physical infrastructure. Let’s take a look at what’s driving their growth, what their financials look like, and where the risks lie.

The Russell indices are reconstituted every June, which means that the index provider reclassifies companies into the appropriate size category based on their market capitalization as of the cut-off date. The maximum threshold for remaining in the small-cap Russell 2000 index was set this year at roughly $5.7 billion. All three companies in question exceeded this threshold by a wide margin, with Bloom Energy surpassing it by more than…