Bloom Energy Corp., Astera Labs, Cheniere Energy and Everpure top a list of companies that could be added to the S&P 500 as part of the index's quarterly rebalancing that will occur later this month.

Any changes to the benchmark index likely will be announced Friday after the close of trading, and the changes likely will go into effect around the time of the rebalancing on Sept. 21.

Each quarter, S&P Dow Jones Indices, which oversees the S&P 500, rebalances the index-along with the S&P MidCap 400 and S&P SmallCap 600)-to reflect changes in component share counts and other factors.

Index changes often take place in conjunction with the rebalancing. In June, for instance, Marvell Technology and Flex were added to the S&P 500.

Companies are eager for admission into the S&P 500 because of the prestige and the bump in their stock price that often comes when the news is announced. Index buying also can boost shares of newly admitted companies-an estimated 30% or more of the S&P 500 is held by index funds.

Bloom, Astera, Cheniere, and Everpure are among the largest companies by market value that aren't included in the S&P 500 index. Stephens analyst Melissa Roberts recently identified them as top candidates for admission into the benchmark index.

Companies with large market values generally get added to the S&P 500, assuming they meet the index's profitability targets of GAAP (generally accepted accounting principles) profits in the most recent quarter and cumulative positive GAAP earnings over the past year.

In a client note, Roberts wrote that she sees two or three changes in the index to be announced along with the rebalancing.

Bloom and Cheniere are the largest companies by market value that are eligible for inclusion in the index, with market values of about $60 billion-well above the current minimum of $22.7 billion.

Cheniere has been eligible for some time. It could finally get added given the strength in the energy sector this year, and because no energy stocks have been added to the index since 2022.

Other possible additions are Credo Technology Group, Heico, Rocket Cos., and Royalty Pharma, Roberts noted.

One company that won't be added, however, is SpaceX., which went public in June. S&P Dow Jones Indices didn't relax its requirement that companies have be public for 12 months before being considered for S&P 500 inclusion. The Nasdaq eased its rules that allowed SpaceX to be included in the Nasdaq 100 index in July.

S&P Dow Jones Indices generally drops companies from the S&P 500 that have the lowest market values to make room for new members.

Trade Desk, Builders FirstSource, Norwegian Cruise Line Holdings, Molson Coors, and Mosaic recently had the five lowest market values in the index at under $8 billion. There are only about 10 companies left in the index with market caps under $10 billion.