RKLB vs YSS: 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: YSS 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. RKLB and YSS 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 RKLB and YSS 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.

Rocket Lab (RKLB) is a space company that builds rockets and spacecraft and provides end-to-end space services. Its established business is the Electron, a small orbital launch vehicle that is one of the most frequently flown small rockets in the world, carrying satellites for commercial, government, and defense customers. Rocket Lab is developing Neutron, a larger, partly reusable medium-lift rocket intended to compete for bigger payloads and constellation deployments, directly targeting the market SpaceX dominates.

Full RKLB guide

York Space Systems, Inc. (NYSE: YSS) is a vertically integrated space and defense prime headquartered in Greenwood Village, Colorado. Founded in 2012 and formerly known as Yellowstone Midco Holdings II, it designs, produces, integrates, and operates spacecraft and constellations built on standardized satellite platforms (S-CLASS, LX-CLASS, and M-CLASS). Its largest customer is the US Space Development Agency, where it has been a prime awardee across the Proliferated Warfighter Space Architecture (PWSA) tranches, and it is positioned into national-security programs tied to missile tracking and the Golden Dome initiative. The company went public in late January 2026 and has been acquiring suppliers, including propulsion maker Orbion Space Technology and solar-technology firm Solestial, to build out a more vertically integrated stack.

Full YSS guide

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

• RKLB drivers: Neutron medium-lift rocket; Space Systems growth.
• YSS drivers: Government space-architecture demand; Backlog conversion and revenue growth.

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: Rocket Lab is not yet consistently profitable and invests heavily in Neutron, so cash burn and capital needs are real until that program generates revenue. For YSS, york is not yet profitable and reported a large trailing net loss, so its valuation embeds expectations of future growth and margin improvement that may not materialize.

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 RKLB if you believe its drivers more; YSS 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 RKLB and YSS guides.

RKLB. Rocket Lab trades as a high-growth space name valued on its Space Systems revenue and the future option value of Neutron rather than current profits. The premium price-to-sales multiple reflects the launch-plus-systems opportunity and defense tailwinds, balanced against losses and Neutron execution risk. Valuation is highly sensitive to Neutron milestones and launch cadence.

YSS. York trades at roughly 6 to 8 times trailing revenue with no positive earnings, a valuation typical of a high-growth, recently public defense-space name. Backlog of about $642M and 2026 guidance imply continued strong growth, but the net loss and heavy investment mean the market is pricing future execution rather than current profits. Figures are approximate and drawn from mid-2026 public sources.

Headline figures (approximate, early 2026): RKLB shows revenue (ttm) ~$500 million, revenue growth Strong double-digit, gross margin Positive and improving, operating margin Negative (investing in Neutron); YSS shows revenue (ttm) ~$396M, 2025 revenue ~$386M (+52% YoY), 2026 revenue guidance ~$545M to $595M, net income (ttm) ~-$249M (net loss).

RKLB and YSS 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 RKLB and YSS exposure against your real portfolio. It is not an investment adviser.