FTSE Russell has released a preliminary list of companies set to enter or leave its U.S. indexes at the end of June as part of its annual reconstitution, which occurs to reflect market changes from the previous year.

And the results tell a tale of the growing gap between the largest and smallest cap stocks.

“Each June, the Russell U.S. index family is realigned to reflect market changes in the last year,” said a press release. “This closely watched market event impacts more than $9 trillion in investor assets benchmarked to or invested in products based on the Russell U.S. indexes and concludes in traditionally one of the highest trading volume days of the year on major U.S. equity exchanges. Record volume is anticipated around the 2020 Russell Rebalance due to index changes to reflect volatile markets in the start of this year.”

Overall, U.S. total equity market capitalization is down one per cent, while the market cap of the 10 largest stocks was up more than 23 per cent. And for the first time in history for the FTSE Russell’s U.S. indexes, there are companies exceeding US$1 trillion in total market cap, with three hitting this milestone. Meanwhile, the smallest stock featured in the small cap index reconstitution has a US$94.8 million market cap, which is first time since 2009 that the smallest stock is less than US$100 million.

“While overall capitalization for the U.S. equity market stayed relatively flat this year, our 2020 annual Russell U.S. indexes reconstitution tells an interesting story about divergence between the largest and smallest U.S. stocks,” said FTSE Russell director of product management, Catherine Yoshimoto.

The relative strength in U.S. large caps helped push that divergence. The market capitalization breakpoint, separating companies in the U.S. large-cap Russell 1000 index and the U.S. small-cap Russell 2000 index, decreased by the more than 16 per cent to US$3 billion.

The FTSE Russell will be publishing updates to its preliminary list this month and the final index reconstitution will conclude after markets close on June 26.