Sifting through countless of stocks in the Office REITs industry can be tedious, and sometimes two stocks are just too similar to judge which is the better investment. If you’re on the fence about investing in COPT Defense Properties or SL Green Realty Corp. because you’re not sure how they measure up, it’s important to compare them on a few factors before making your decision.

Read on to learn how COPT Defense Properties and SL Green Realty Corp. compare based on key financial metrics to determine which better meets your investment needs.

About COPT Defense Properties and SL Green Realty Corp.

COPT Defense Properties, an S&P MidCap 400 Company, is a self-managed REIT focused on owning, operating and developing properties in locations proximate to, or sometimes containing, key U.S. Government defense installations and missions (referred to as its Defense/IT Portfolio). The Company’s tenants include the USG and their defense contractors, who are primarily engaged in priority national security activities, and who generally require mission-critical and high security property enhancements. As of June 30, 2026, the Company’s Defense/IT Portfolio of 202 properties, including 24 owned through unconsolidated joint ventures, encompassed 23.3 million square feet and was 96.4% leased. COPT Defense Properties was incorporated in 1988 and is based in Columbia, United States.

SL Green Realty Corp., Manhattan's largest office landlord, is a fully integrated real estate investment trust, or REIT, that is focused primarily on acquiring, managing and maximizing the value of Manhattan commercial properties. As of June 30, 2026, SL Green held interests in 54 buildings totaling 30.6 million square feet, which included ownership interests in 29.2 million square feet and 1.4 million square feet securing debt and preferred equity investments, excluding fund investments, and managed 4 buildings totaling 0.9 million square feet owned by third parties. SL Green Realty Corp. was incorporated in 1980 in Maryland and is based in New York.

Latest Office REITs and COPT Defense Properties, SL Green Realty Corp. Stock News

As of October 8, 2026, COPT Defense Properties had a $3.8 billion market capitalization, compared to the Office REITs median of $945.0 million. COPT Defense Properties’s stock is up 20.4% in 2026, down 0.3% in the previous five trading days and up 17.23% in the past year.

Currently, COPT Defense Properties’s price-earnings ratio is 23.3. COPT Defense Properties’s trailing 12-month revenue is $788.1 million with a 20.8% net profit margin. Year-over-year quarterly sales growth most recently was 3.9%. Analysts expect adjusted earnings to reach $1.445 per share for the current fiscal year. COPT Defense Properties currently has a 3.8% dividend yield.

As of October 8, 2026, SL Green Realty Corp. had a $3.5 billion market cap, putting it in the 63rd percentile of all stocks. SL Green Realty Corp.’s stock is up 5.5% in 2026, down 0.8% in the previous five trading days and down 17.15% in the past year.

Currently, SL Green Realty Corp. does not have a price-earnings ratio. SL Green Realty Corp.’s trailing 12-month revenue is $998.0 million with a -16.7% net profit margin. Year-over-year quarterly sales growth most recently was 27.3%. Analysts expect adjusted earnings to reach $-1.617 per share for the current fiscal year. SL Green Realty Corp. currently has a 5.0% dividend yield.

How We Compare COPT Defense Properties and SL Green Realty Corp. Stock Grades

Stock evaluation requires access to huge amounts of data and the knowledge and time to sift through it all, make sense of financial ratios, read income statements and analyze recent stock movements. AAII created A+ Investor, a robust data suite that condenses data research in an actionable and customizable way suitable for investors of all knowledge levels, to help investors streamline and work through such data.

AAII’s proprietary stock grades come with A+ Investor. These offer intuitive A‐F grades for each of five key investing factors: value, growth, momentum, earnings estimate revisions and quality. Here, we’ll take a closer look at COPT Defense Properties and SL Green Realty Corp.’s stock grades to see how they measure up against one another.

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COPT Defense Properties and SL Green Realty Corp. Stock Value Grades

Company	Ticker	Value
COPT Defense Properties	CDP	D
SL Green Realty Corp.	SLG	C

Successful stock investing involves buying low and selling high, so stock valuation is an important consideration for stock selection.

Buying stocks that are going to go up typically means buying stocks that are undervalued in the first place, although momentum investors may argue that point.

AAII’s A+ Investor Value Grade derives from a stock’s value score. The Value Score is the percentile rank of the average of the percentile ranks of the price-to-sales ratio, price-earnings ratio, enterprise-value-to-EBITDA (EV/EBITDA) ratio, shareholder yield, price-to-book-value ratio and price-to-free-cash-flow ratio. The score is variable, meaning it can consider all six ratios or, should any of the six ratios not be valid, the remaining ratios that are valid. To be assigned a Value Score, stocks must have a valid (non-null) ratio and corresponding ranking for at least two of the six valuation ratios.

Stocks with a Value Score from 81 to 100 are considered deep value, those with a score between 61 and 80 are a good value and so on.

COPT Defense Properties has a Value Score of 35, which is Expensive. SL Green Realty Corp. has a Value Score of 45, which is Average.

The Value Stock Winner: No Clear Winner

Neither COPT Defense Properties or SL Green Realty Corp. has a high enough value grade to be considered a “winner.” Investors who are considering these companies should do additional due diligence and research to see if either could be a good addition to their portfolio. It’s important to look at a wide range of financial metrics in order to determine if COPT Defense Properties or SL Green Realty Corp. is the better investment when it comes to value.

COPT Defense Properties and SL Green Realty Corp.’s Momentum Grades

Company	Ticker	Momentum
COPT Defense Properties	CDP	C
SL Green Realty Corp.	SLG	C

Momentum grades help to uncover stocks experiencing anomalously high rates of return; research finds that stocks with high relative levels of momentum tend to outperform, whereas those with low levels of momentum tend to continue underperforming. Momentum is based on the price change of a stock over a specified period relative to all other stocks.

Typically, AAII looks at the weighted relative strength over the trailing four quarters. The weighted four-quarter relative strength rank is the relative price change for each of the past four quarters. The most recent quarterly price change is given a weight of 40% and each of the three previous quarters are given a weighting of 20%.

COPT Defense Properties has a Momentum Score of 56, which is Average. SL Green Realty Corp. has a Momentum Score of 41, which is Average.

The Momentum Stock Winner: No Clear Winner

Neither COPT Defense Properties or SL Green Realty Corp. has a strong enough Momentum Grade to be considered a “winner.” Investors considering these companies should do additional due diligence and research to see if either could be a good addition to their portfolios. It’s important to look at a wide range of financial metrics in order to determine if COPT Defense Properties or SL Green Realty Corp. is the better investment when it comes to momentum.

COPT Defense Properties and SL Green Realty Corp.’s Estimate Revisions Grades

Company	Ticker	Earnings Estimate
COPT Defense Properties	CDP	na
SL Green Realty Corp.	SLG	B

Earnings estimate revisions scores consider the magnitude of a company’s earnings surprise in its last two reported fiscal quarters. Often, positive surprises beget further positive surprises‐or at least continued sales growth (the exact opposite is generally true, too).

Estimate revisions offer an indication of what analysts are thinking about the short-term prospects of a firm. Estimate revisions are based on the statistical significance of a firm’s last two quarterly earnings surprises and the percentage change in its consensus estimate for the current fiscal year over the past month and past three months.

COPT Defense Properties does not have a meaningful Earnings Estimate Score. SL Green Realty Corp. has a Earnings Estimate Score of 64, which is Positive.

The Earnings Estimate Revisions Stock Winner: Undetermined

If you are strictly an investor who focuses on earnings estimate revisions, you may want to add SL Green Realty Corp. to your watch list. However, because only one of the companies in our comparison has a valid Earnings Estimate Revisions Grade, we cannot call it a clear winner. Evaluation of the other grades for both companies is necessary in order to understand which stock is the better investment based on AAII’s proprietary scores and analysis.

Other COPT Defense Properties and SL Green Realty Corp. Grades

In addition to Estimate Revisions, Value and Momentum, A+ Investor also provides grades for Growth and Quality.

Growth investing builds on the idea that stocks of companies exhibiting strong, consistent and prolonged growth outperform those of slower-growth companies. AAII measures growth through consistency of annual sales growth, five-year sales growth rankings adjusted for extreme levels, and consistency of positive annual cash from operations.

AAII’s A+ Investor Quality Grade comes from the ranking of key metrics. Specifically, the quality grade is the percentile rank of the composite of return on assets (ROA), return on invested capital (ROIC), gross profit relative to assets, buyback yield, change in total liabilities to assets, accruals, Z double prime bankruptcy risk (Z) score and F-Score.

These 2 key factors, when combined with the above, provide a holistic view into a particular stock. Further, by joining A+ Investor you can see whether COPT Defense Properties and SL Green Realty Corp. pass any of our 60+ stock screens that have outperformed the market since their creation.

So, Which Is the Better Investment, COPT Defense Properties or SL Green Realty Corp. Stock?

Overall, COPT Defense Properties stock has a Value Score of 35, Momentum Score of 56 and Estimate Revisions Score of .

SL Green Realty Corp. stock has a Value Score of 45, Momentum Score of 41 and Estimate Revisions Score of 64.

Comparing COPT Defense Properties and SL Green Realty Corp.’s grades, scores and metrics can act as a solid basis to determine whether they may be a good investment or not. You’ll also want to look at your portfolio’s asset allocation as well as your risk tolerance and financial goals to see if either of these stocks would make a good fit for you. AAII can help you figure out which investments align with your individual needs and preferences.

Investors are encouraged to do their own due diligence and research. In this way, individuals can effectively become managers of their own assets‐without having to rely on others for financial independence. You can count on AAII for timeless articles on financial planning and stock-picking, unbiased research and actionable analysis.

A+ Investor adds to our qualitative teaching with a powerful data suite to help you whittle down investment choices to find stocks, exchange-traded funds (ETFs) or mutual funds that meet your needs.

AAII Disclaimer

We make no representations or warranties that any investor will, or is likely to, achieve profits similar to those shown, because past, hypothetical or simulated performance is not necessarily indicative of future results. Before making an investment decision, you should consider your circumstances and whether the information on our content is applicable to your situation. This information was prepared in good faith, and we accept no liability for any errors or omissions. The full disclaimer can be read here.