It’s easy to think of the major U.S. stock market indexes as permanent and unchanging over the decades. The financial equivalent of Mount Rushmore. The Dow Jones Industrial Average was created in 1896 and has been capturing news headlines and dominating dinner conversations ever since. It was there throughout both World Wars. And Watergate. And the first moon landing. And September 11, 2001.

Maybe.

But unlike that famous monument chiseled into the South Dakota hills, the corporate icons enshrined in the Dow Jones aren’t exactly set in stone. In fact, there have been 59 changes made over the years by a special committee.

Not a single one of the original 12 members still exists today. American Sugar Refining. United States Leather Company. Tennessee Coal, Iron and Railroad Company. All have been dissolved, broken up by antitrust action, or absorbed by acquisition.

While it’s sad to see constituents disappear, it’s usually for the best. In theory, they are swapped out with a replacement more representative of the current economy. Out with the old, in with the new. There is no place for nostalgia.

Retailer Woolworth gave up its spot to Walmart (NYSE: WMT) in 1997. Goldman Sachs (NYSE: GS) replaced Alcoa (NYSE: AA). AT&T (NYSE: T) was shoved aside for Apple (NSDQ: AAPL). Sears Roebuck was removed in favor of Intel (NSDQ: INTC), which itself was supplanted last year by Nvidia (NSDQ: NVDA).

At any point in time, the 30 members of the Dow Jones Industrials are a good proxy for the performance of the overall market. But those 30 names will continue to change.

Of course, the same is true of the S&P 500. The index is regularly reconstituted and rebalanced. Some of the outgoing members have been acquired. Others have lost their mojo and performed poorly, sometimes shrinking from large-cap to mid-cap territory and no longer meeting requirements.

Whatever the reason, the specific constituents of the S&P are always in a state of flux. Not surprisingly, some of the latest additions are engaged in new-economy industries such as cloud security and cryptocurrency.

Considering there are trillions in mutual fund and ETF assets that mirror this key benchmark, it’s not uncommon for new members to see a measurable bump in stock price upon (or even before) initiation as fund managers add these new names to their portfolios.

Which brings us to the heart of today’s article. On September 22, Caesar’s Entertainment, Enphase Energy and MarketAxess will all be bumped from the S&P 500. Let’s meet the replacements:

AppLovin (NSDQ: APP) – As the name implies, this unique business makes software tools utilized by designers and programmers to optimize mobile phone applications. The shares have been near the top of the market leaderboard, rising 8-fold from their IPO in 2021 to reach a new high of $545 this week.

That performance has been driven by booming top and bottom-line growth, with revenues spiking 74% so far this year and net income skyrocketing 156%.

A leader in the burgeoning advertising technology (or adtech) space, Applovin has branched well beyond its mobile gaming roots into AI-driven marketing and data analytics. Helping advertisers and content publishers better connect with audiences, the Palo-Alto company has seen advertising spending on its platform quadruple since the launch of its Axon AI engine two years ago.

The shares spiked 11% on Monday’s news.

Robinhood (NSDQ: HOOD) — Robinhood was built by a pair of Stanford classmates who wanted to shake up the status quo and make the markets more accessible to everyday investors.

In stark contrast to blue-blood brokers that won’t even meet with a client unless they have at least six figures of investable assets, Robinhood has no account minimums and actively courts the business of newbies making their first investment.

Launched in 2015, the platform quickly became popular with twenty-something Millennials and Gen Zers. It attracts droves of younger workers who diligently set aside a few bucks from each paycheck.

Robinhood helped popularize the “meme” stock revolution, but enables clients to dabble in everything from options and futures to cryptocurrency. With a zero-commission structure, the company generates the bulk of its income through order flow. It acts as an intermediary and receives payments for feeding the buy and sell orders of millions of loyal users to market makers who execute the trades.

Robinhood now has 27.4 million active accounts, having added more than 2.5 million over the past 12 months. Meanwhile, those customers have deposited $58 billion in assets, lifting the total invested across the firm’s various platforms to $279 billion.

While profits were elusive a few years ago, they have begun to pile up as this scaleable business continues to grow – net income surged more than 100% last quarter to $386 million.

Robinhood holds appeal for numerous banks, brokerages, and even fintech companies like Sofi (NSDQ: SOFI) eager for a larger slice of this lucrative pie. Inclusion in the S&P only enhances its appeal.

Emcor (NYSE: EME) – Emcor is a trusted engineering and infrastructure firm that works with commercial, industrial and government customers around the globe. It designs, installs and maintains electrical, mechanical, air conditioning, lighting and power generation systems.

You’ll find Emcor involved in all kinds of large-scale projects, from hospitals to EV battery plants to water treatment facilities, but the biggest growth catalyst right now is data center construction. Demand in this key end market has helped drive project backlog to a record $11.9 billion.

Emcor has a healthy pipeline, thanks in part to the reshoring of semiconductor foundries and other manufacturing activity. Year-to-date revenues of $8 billion are running 15% of last year’s pace, while earnings are up 27% to $12.11 per share and on track for a record-high $25 per share in 2025.

With a strong balance sheet, management has been returning a big chunk back to stockholders. Quarterly dividends were hiked nearly 40% last year, to go with $300+ million in share repurchase authorizations.