A headline RPO is not backlog until you strip pass-through, check the recognition schedule, and read the termination clause

Claim

"$25.4B of backlog against $680M of revenue" is the kind of number that ends an analysis before it starts. It should start one. RPO is a disclosure with named exclusions and a disclosed schedule, and both live away from the headline.

Evidence — CBRS, Q2 2026

RPO $25.4B at 2026-06-30 against TTM revenue of $680.7M — roughly 37x trailing sales. Four discounts, each from the filings:

Gross-basis pass-through. The 10-Q states pass-through costs "are included in the transaction price and remaining performance obligations," and separately that "these pass-through revenues are not part of our core technology or service offerings" and "will increase significantly." An unknown but growing share of the RPO carries no margin.
The schedule is long. Only ~15% recognises within 24 months; 43% in months 25–48; the remainder after. A multiple computed against trailing revenue implies a velocity the schedule does not support.
The change is worse than the level. RPO went $24.6B → $25.4B over six months while $373.5M was recognised — roughly $1.2B of net new bookings against a $25.4B base. The headline grew 3% while the business it represents did not visibly compound.
The customer holds a termination right. If Cerebras misses capacity timelines or service levels, OpenAI "has the right to terminate a portion or all of the agreement" — and may then seize control of the $1.0B working-capital loan account and demand immediate repayment. The largest asset on the thesis is contingent on flawless multi-year execution.

How to run the check

Grep the filing for remaining performance obligation, then read the whole paragraph, not the number. Exclusions and the recognition schedule are in the same note.
Grep for pass-through, gross basis, principal / agent — gross-basis recognition is the tell that the top line contains someone else's costs.
Compute ΔRPO + revenue recognised = gross new bookings. This is the number that tells you whether demand is compounding; the RPO level tells you what was signed once.
Read the termination and service-level clauses on any RPO concentrated in one counterparty. A backlog one customer can cancel is a forecast, not an asset.
Sanity-test the funding: RPO that requires capex the balance sheet cannot fund is a claim on future financing as much as on future revenue.

Related: [[pattern-customer-warrants-are-contra-revenue-that-buys-the-backlog]] (same filing), [[pitfall-lease-financed-capex-hides-from-the-fcf-line]], [[principle-primary-source-beats-vendor]].