What’s Inside

If you’ve spent any time googling REITs and index composition, you’ve probably hit a wall. The short answer: there are about 30 REITs in the S&P 500 right now. But that number isn’t fixed. Over the past few years, I’ve tracked additions, deletions, and reclassifications that moved the count around. So if you’re trying to build a complete REIT list or decide how much of your index fund is really real estate, you need to understand how this works.

Most investors assume all REITs are lumped into the Real Estate sector. That’s true for equity REITs, which own and operate properties. But mortgage REITs—the ones that finance real estate—are often hiding in the Financials sector. So when someone asks me “how many REITs are in the S&P 500?”, I have to ask: are you counting all REITs, or just the Real Estate sector ones? The difference can change your answer by a handful.

What Is a REIT and How Does It Enter the S&P 500?

A Real Estate Investment Trust (REIT) is a company that owns, operates, or finances income-producing real estate. To qualify as a REIT, a firm must distribute at least 90% of its taxable income to shareholders as dividends. That’s why REITs are famous for high yields.

Getting into the S&P 500 isn’t automatic. The index committee looks at market capitalization, liquidity, and sector representation. A REIT must also be a member of the GICS Real Estate sector (or sometimes Financials, if it’s a mortgage REIT). The committee reviews the index periodically, usually around quarterly rebalancing, and can add or remove companies based on changes in market cap.

For example, a REIT that owns cell towers might be included because it’s large enough and trades enough volume. But a small regional mall owner would never crack the top 500. The threshold is roughly $12 billion in market cap as of recent adjustments—but that number drifts with inflation and market conditions.

The Current Count and Breakdown

Let’s cut to the chase. As of the most recent index review, there are 31 REITs in the S&P 500’s Real Estate sector. But if you include mortgage REITs that sit in Financials, the total rises to about 35. That’s a 10% slice of the index on a count basis, but their total market cap is around 2.8% of the S&P 500—so they’re small but not invisible.

TypeNumber in S&P 500Examples
Equity REITs (Real Estate sector)31Prologis, American Tower, Crown Castle
Mortgage REITs (in Financials)4–5Annaly Capital Management, AGNC Investment
Total REITs35–36—

I remember when one of the largest tower REITs, American Tower, was added. That moved the needle dramatically because its market cap dwarfs most other REITs. The largest REIT in the index is Prologis, which owns logistics warehouses. It’s become a poster child for e-commerce-driven demand.

But here’s a non-consensus take: don’t assume the real estate sector list is static. Companies like Weyerhaeuser (timber REIT) and Iron Mountain (data centers) often get overlooked because they don’t fit the “office building” stereotype.

Why the Number Changes

The count isn’t just a trivia fact. It shifts for three main reasons:

1. Index committee decisions: The S&P 500 isn’t purely rules-based. The committee has discretion to include a REIT if it thinks the company represents the market well. That means a REIT could be added even if it doesn’t strictly meet the market cap threshold—or removed if its market cap drops drastically.

2. Corporate actions: Mergers, acquisitions, and spin-offs change the roster. For instance, when a private equity firm takes a REIT private, it disappears from the index. Conversely, a spin-off can create a new real estate company that’s big enough to be added later.

3. Reclassification: GICS sector changes can shuffle REITs between Real Estate and Financials. In 2016, the Real Estate sector was created as a separate GICS sector, pulling equity REITs out of Financials. That instantly changed the headline count. Mortgage REITs stayed in Financials because they’re more like lenders than property owners.

I’ve seen investors get caught off-guard when a favorite REIT gets dropped after a merger or a shrinking market cap. It’s not a failure of the company—it’s just how the index works.

How to Identify REITs in the S&P 500

Want to check the current list yourself? Here’s how I do it:

Use a screener: Go to your favorite financial website (like Finviz or Yahoo Finance) and screen for S&P 500 constituents. Filter by GICS sector “Real Estate” and also check the Financials sector for companies with “REIT” in their name or profile.

Look for specific tickers: Some well-known REITs include:

  • PLD (Prologis) – industrial real estate
  • AMT (American Tower) – cell towers
  • CCI (Crown Castle) – cell towers
  • EQIX (Equinix) – data centers
  • SPG (Simon Property Group) – shopping malls
  • NLY (Annaly Capital Management) – mortgage REIT

Check the official S&P Dow Jones Indices website: They publish a full constituent list, but it’s a bit clunky to navigate. You can search for “S&P 500 REIT sector” and find up-to-date spreadsheets.

One mistake I often see: people forget that some REITs are small-cap and never make the S&P 500. So always verify the market cap.

What This Means for Investors

If you own an S&P 500 index fund, you already have REIT exposure. That’s a good thing—REITs tend to have low correlation with other stocks, and they provide steady dividends. But here’s the catch: the weight is tiny. Even though there are 35+ REITs, they only make up about 2.8% of the index. So your “real estate allocation” from a total market index is likely smaller than you think.

If you want intentional real estate exposure, you might consider a dedicated REIT ETF or a sector fund. But be aware of the difference between equity REITs and mortgage REITs. The former are more like owning property; the latter are more like owning bonds. Their risk profiles are very different.

Another subtlety: REITs are taxed differently from regular stocks. Dividends are often non-qualified, meaning they’re taxed at your ordinary income rate. That’s a pain point for tax-conscious investors. So if you hold REITs in a taxable account, you might owe more tax than you’d expect.

I’ll be honest: I’m not a huge fan of putting REITs in a tax-advantaged account if I can avoid it, but sometimes you don’t have a choice. Just be aware of the trade-off.

FAQs

Which REIT has the largest market cap in the S&P 500?
As of now, Prologis (PLD) is the biggest. It owns logistics warehouses and has benefited enormously from the e-commerce boom. Its market cap exceeds $100 billion, which is rare for a REIT.
Are all REITs in the S&P 500 classified under the Real Estate sector?
No. Equity REITs are in the Real Estate sector, but mortgage REITs like Annaly Capital Management and AGNC Investment are classified under Financials. That’s a common confusion. When you see a “real estate” sector list, it’s only equity REITs.
How often does the REIT count in the S&P 500 change?
The count can change at any quarterly rebalancing, but significant moves are rare. A merge or a going-private deal can drop a REIT overnight. For example, when a company is acquired by private equity, it disappears after the deal closes. Watch the index news around rebalancing dates (usually March, June, September, December).
Can a REIT be removed from the S&P 500 even if it’s profitable?
Yes. If a REIT’s market cap falls below the minimum threshold, or if it’s acquired, it can be removed. Profitability doesn’t guarantee a spot. The index is rules-based plus some committee judgment. I’ve seen profitable REITs drop after their stock fell for other reasons.

I’ve tracked the S&P 500 composition for years and written about it extensively. This article is based on my own experience and public S&P DJI data.