Getting into the S&P 500 is a big deal for any company. It is an even bigger deal when your stock has been on a roller coaster.
Reddit just learned that firsthand. Its shares jumped 11% in after-hours trading the moment S&P Dow Jones Indices announced the company would join the benchmark index on August 18. The social media firm is taking the spot vacated by AvalonBay Communities, a real estate investment trust.
The bounce makes sense. Index-tracking fund managers have to buy shares of every company in the S&P 500, so they are about to become forced buyers of Reddit stock. That kind of guaranteed demand tends to push prices up.
This is how the index works. The benchmark tracks the 500 largest U.S. companies by market value, and billions of dollars in mutual funds and exchange-traded funds are built to mirror it. When a stock joins the list, every one of those funds needs to own it.
Reddit is now the second pure-play social media firm in the index, with Meta being the other. That is a notable spot. Pinterest and Snap both went public earlier than Reddit but have smaller market capitalizations, which kept them out of the club.
Twitter used to be in the index, but it got removed in 2022 after Elon Musk bought the company and took it private. It now operates as X under SpaceX.
So Reddit is joining a pretty short list. On top of that, Sun Communities is moving into the S&P MidCap 400 as part of the same reshuffle, replacing Webster Financial.
The index news is the headline, but Reddit's business has a story of its own. In late July, Reddit said revenue rose more than 60% for the eighth consecutive quarter. That is a run most public companies would dream about.
The catch: the stock had taken a hit before this announcement. Reddit told investors that "search referrals were choppy," which spooked the market. The concern was that Reddit leans too heavily on Google to bring in new users. If Google changes how it sends traffic, Reddit feels it.
CEO Steve Huffman pointed to a likely cause. Google has been pushing its Gemini-powered AI Overviews at the top of search results, which means people get answers without clicking through to websites like Reddit. Less clicking means less traffic.
That tension is the real story here. Reddit has the growth numbers to justify a spot among America's biggest companies, but it also has a dependency that could bite later. The index inclusion is a milestone, but it does not fix that underlying question.
If you own a fund that tracks the S&P 500, you are about to own Reddit whether you picked it or not. That is the trade-off with index funds - you get the winners, but you also get whatever comes with them.
But the longer-term question is whether Reddit can keep its growth streak alive while Google keeps changing the rules of the internet. The company has answered that question well so far.
Reddit is still a young public company with a volatile stock. The index addition is a vote of confidence from the people who rank America's largest businesses. What happens next depends on whether Reddit can keep search referrals steady and keep finding new ways to grow.
That is the part no index inclusion can guarantee.
