The S&P 500 (^GSPC -1.11%) has long been the benchmark of performance for many investors. Because it comprises about the 500 largest stocks listed on the U.S. index, it tracks companies from multiple industries, giving investors a good feel for how the overall market is doing.

Although the index was created in 1957, it is possible to extend it back to 1927 using the entrance criteria the index has. By looking at these annual returns, you can discover some interesting trends, including the one that we're heading into. So, what do the historical numbers say the market will do in 2025?

The market reflects the dot-com boom during the late '90s

The market has been incredibly strong over the past two years, as it has returned over 20% (if the 2024 returns hold up to finish the year). That doesn't happen all that often. In fact, it has only happened five times since 1927.

The market is heading into year three of that run. What happened the previous five times the market returned 20% for two years in a row? The answer: It's a mixed bag.

  • 1937 return: -39%
  • 1956 return: 2.6%
  • 1997 return: 31%
  • 1998 return: 26.7%
  • 1999 return: 19.5%

If it's another year like 1937, investors may be in for some pain. However, it could also be like the late '90s, when investors enjoyed nearly five straight years of 20% or more returns.

What happened in the late '90s? There was a tech boom associated with the internet. That ended extremely poorly a few years after the run, but there was significant investing success during the run.

The internet turned out to be a huge technological success, even if many of the companies involved with it didn't give investors great returns over the long term (during the rise, they gave investors huge gains).

That sounds incredibly similar what is happening today, as artificial intelligence (AI) stocks are all the investing rage. Many people are predicting that the current AI revolution will have a similar effect on work and society as the internet did, so it's quite fitting to predict the market will act much as it did in the late '90s.

What am I doing in 2025?

As we head into 2025, I'm planning on being an opportunistic buyer. If I see a company I like trading at a reasonable price, I'll invest. Otherwise, I'm perfectly content with just investing in a broad market index, like the S&P 500.

That way, if AI stocks do go down, it won't be as painful as being 100% invested in the AI universe. Now, the S&P 500 is heavily weighted toward some of these AI companies, as the S&P 500 is a market cap-weighted index, so it won't be in the clear if there there is a pullback. However, various healthcare, financial, and consumer goods companies will help prop it up.

On another note, there's nothing special about turning the calendar to 2025. Although it marks a new year, the market is a continuous entity, so the calendar flip from 2024 to 2025 isn't really a great milestone to judge it by because there can be specific events that happen in the middle of a year that would truly define a new stage in the market.

With that in mind, the S&P 500 is still a great place to put money in the market, as it is a fairly well-balanced index. However, if you're looking for more upside, there are some specific companies within that index that look like fantastic buys now, and I'll be scooping them up in 2025 as well.