From verified module to rated-pool pre-screen in one API call.

The eligibility rule

KeyScore ≥65 on the source module = eligible to enter a pool. Below that, the module stays in the registry but gets routed elsewhere (rehab, supplemental QA, scrap).

The grading function

keystone_pool_grade() is a Postgres function that takes the weighted KeyScore across the pool's eligible modules and emits an indicative letter grade — the same shape the downstream NRSRO partner will use when issuing the official credit rating:

• AAA-equivalent — weighted KeyScore ≥90
• AA-equivalent — 85–89
• A-equivalent — 80–84
• BBB-equivalent — 72–79
• NR (not graded) — <72

A pool of 2 × KeyScore-92 modules = AAA-equivalent indicative grade, $85,968 collateral, securitization-input-ready.

Important. The pool grade Keystone outputs is an indicative pre-screen used by NRSRO-registered partners as one input into their own independent credit-rating process. When a SEC-registered securitization requires an official credit rating, that rating is issued by the NRSRO partner (KBRA, DBRS Morningstar, Fitch, etc.) — not by Keystone. See the partner-model architecture for the full counterparty mapping.

The pool-summary API

POST /functions/v1/pool-summary returns:

• grade — AAA / AA / A / BBB / NR equivalent (indicative)
• eligible_collateral — total dollar value
• weighted_keyscore — the weighted-by-value KeyScore
• securitization_input_ready — boolean (i.e. ready to pass to an NRSRO partner)
• tranches — senior 70% / mezz 20% / equity 10%

Revenue model — partner-aware

Keystone's Capital Rail revenue is structured to keep regulated activity with the licensed counterparty:

• SaaS analytics subscription — per-pool or per-issuer pricing for the underwriting analytics + pre-screen API
• Partner revenue-share with the broker-dealer — when a SEC-registered broker-dealer partner places a securitization using Keystone's pre-screen, Keystone receives a share of the broker-dealer's transaction economics
• Partner data-feed fee with the NRSRO — when an NRSRO partner uses Keystone's pool analytics as input into an official credit rating, Keystone receives a data-feed licensing fee

Keystone does not take gain-on-sale directly and is not registered as a broker-dealer under §15 of the Exchange Act. The economics flow through licensed counterparties.

Who pays for it

GSEs (Fannie, Freddie), LIHTC syndicators (Boston Capital, RBC Community Investments, Raymond James Affordable Housing, Enterprise CHP), debt funds, community development financial institutions, and private credit funds — anyone underwriting a pool of modular collateral and needing a defensible pre-screen before engaging an NRSRO partner.

The same KeyScore the manufacturer's QA team trusts is the same number the lender pre-screens against. The official credit rating, when required, is issued by an NRSRO partner using that consistent signal.