CSGP vs MCO: Which Is the Better Buy in 2026?

Same yardstick, side by side (as of August 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.

Reading it: CSGP is the cheaper of the two on forward earnings, but cheaper is not the same as better. Pair the valuation with growth (how far the forward P/E sits below the trailing P/E) and risk (beta) before you decide.

The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. CSGP and MCO share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.

This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined CSGP and MCO exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.

CoStar Group is a real-estate information, analytics, and online-marketplace company. Its core commercial franchise sells subscriptions to the CoStar database (property records, leasing, sales comparables, and analytics compiled by hundreds of researchers), LoopNet (the most-visited commercial listing marketplace), and Apartments.com (the leading multifamily rental marketplace). More recently the company has pushed into residential real estate with Homes.com, spending aggressively on marketing to challenge Zillow and Realtor.com. Revenue is largely recurring and subscription-based, which historically produced high margins and consistent growth across dozens of quarters.

Full CSGP guide

Moody's is a global integrated risk-assessment company best known for credit ratings. It operates two main segments. Moody's Investors Service (MIS) rates the creditworthiness of bonds, loans, and other debt instruments issued by corporations, governments, and structured-finance vehicles, earning fees from issuers each time debt is rated. Moody's Analytics (MA) sells subscription software, data, research, and models for credit risk, economic forecasting, regulatory compliance, and increasingly ESG and supply-chain risk. Together with S&P Global, Moody's forms half of an effective duopoly in credit ratings, an industry protected by deep regulatory entrenchment, network effects, and the trust embedded in its ratings over more than a century. The ratings business is highly profitable and cyclical with debt-issuance volumes, while Moody's Analytics provides growing, recurring subscription revenue that smooths the cycle. Founded in 1909 and headquartered in New York, Moody's is a high-margin compounder tied to the global flow of capital and debt.

Full MCO guide

Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.

• CSGP drivers: Commercial data moat and pricing power; Residential expansion with Homes.com.
• MCO drivers: Ratings duopoly and pricing power; Moody's Analytics recurring revenue.

A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: Reported profitability has been thin because of heavy Homes.com marketing, so the residential bet remains unproven and could keep depressing margins if audience and agent revenue disappoint. For MCO, the ratings segment is cyclical: debt issuance falls sharply when interest rates rise quickly or credit markets freeze, directly pressuring MIS revenue.

Growth-minded investors who believe the theme has years to run tend to accept the richer multiple for more upside; value-minded investors lean toward the cheaper forward earnings and steadier profile. Pick CSGP if you believe its drivers more; MCO if you believe its. Many investors hold both, but since they share themes, that is a concentrated bet, not diversification. Decide deliberately and check overlap. For the full detail, see the CSGP and MCO guides.

CSGP. CoStar carries a very high trailing P/E because heavy residential spending has kept net income small relative to its size, so the forward multiple is a more useful gauge. Revenue keeps compounding at double digits and 2026 profit guidance was raised, pointing to a possible margin inflection. The valuation reflects the market pricing in a successful Homes.com build-out rather than current earnings.

MCO. Moody's trades at a premium to the market, reflecting its position in a protected ratings duopoly, high margins, capital-light economics, and the recurring revenue of Moody's Analytics. The valuation embeds steady mid-to-high-single-digit growth and assumes durable issuance volumes over time. The multiple has historically compressed during sharp debt-issuance downturns and re-rated as markets reopened.

Headline figures (approximate, July 2026): CSGP shows revenue (ttm) ~$3.5 billion, 2026 revenue guidance ~$3.78-3.82 billion (16-18% growth), q1 2026 revenue ~$897 million, up ~23% year over year, adjusted eps guidance (2026) ~$1.32-1.39; MCO shows revenue (ttm) ~$7.5 billion, operating margin ~45%, net income (ttm) ~$2.5 billion, eps (ttm) ~$13.50.

CSGP and MCO are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined CSGP and MCO exposure against your real portfolio. It is not an investment adviser.