Mortgage capital-markets terms, defined precisely.
101 entries. Cross-referenced. Linked from feature pages and the API cookbook.
A
AMI (Area Median Income)
The median family income for a defined geographic area, published annually by FFIEC and used to qualify borrowers for income-restricted loan programs.
APR (Annual Percentage Rate)
The total annualized cost of borrowing, including interest and most prepaid finance charges, expressed as a percentage of the loan amount.
ARM (Adjustable-Rate Mortgage)
A mortgage whose interest rate adjusts periodically based on a published index plus a margin, after an initial fixed period.
Audit hash chain
A tamper-evident audit log structure in which each row carries a SHA-256 hash of the previous row + the canonical-JSON form of itself.
B
Base price
The price an investor publishes for a (program, rate, lock period) cell on its ratesheet, before any adjustments, margin layers, or buydown costs.
Basis points (bps)
One basis point equals 0.01% (one one-hundredth of one percent). Mortgage rates and adjustments are typically expressed in bps.
Best execution (BEST_EX)
A pricing mode that finds the highest final price across all eligible investors, optimizing across both rate and investor.
Best-effort delivery
An execution type where the originator commits to attempt delivery; non-delivery carries no penalty.
Buydown
An upfront fee paid to reduce the note rate, either temporarily (2-1 buydown) or for the life of the loan (permanent buydown).
BY_PRICE
A pricing mode that pins a target price (e.g., 100 or 100.5) and returns the rate ladder around that price for each eligible investor.
BY_RATE
A pricing mode that pins a rate and returns the price ladder around that rate for each eligible investor.
C
Capability catalog (formerly RBAC)
An authorization model in which capabilities attach to roles, and roles attach to users and orgs. RateStack ships 12 operational + 7 provider capabilities, published at /v1/capabilities.
CFPB
Consumer Financial Protection Bureau — federal regulator with primary mortgage-rule authority post-Dodd-Frank.
Closing Disclosure (CD)
The TRID-mandated five-page form delivered at least three business days before consummation summarizing the final terms of the loan.
CLTV (Combined Loan-to-Value)
The ratio of all outstanding mortgage balances (first lien + subordinate liens) to the property's appraised value, expressed as a percentage.
Compensation plan
A loan-officer compensation structure binding tier logic (basis points by loan amount, product, or volume) to an officer with an effective range.
Conforming loan
A first mortgage that meets Fannie Mae and Freddie Mac purchase eligibility, including loan-amount limits and product requirements.
correlationId
A unique identifier minted at API ingress and propagated through every log, event, webhook header, and audit row for a single logical request.
Correspondent lender
A lender that originates and funds loans in its own name, then sells them to investor partners on a delivery basis.
D
Dead-letter queue (DLQ)
A queue that holds messages or webhook deliveries that failed after exhausting all retry attempts, queryable and replayable.
Debt-service-coverage ratio (DSCR)
The ratio of property income to debt service, used in DSCR loan qualification and in commercial real estate.
Discount points
Upfront fees paid by the borrower to lower the note rate. One point equals 1.00% of the loan amount.
Documentation type
The level of income and asset documentation provided by the borrower — full doc, alt-doc, bank-statement, asset-depletion, no-doc.
DSCR loan
A non-QM investment-property mortgage qualified on the property's debt-service-coverage ratio rather than the borrower's personal income.
DTI (Debt-to-Income ratio)
The ratio of monthly debt obligations to gross monthly income, expressed as a percentage. Used to qualify borrowers for loan programs.
E
EAD
Electronic Appraisal Delivery — the GSE process for submitting appraisal data prior to loan delivery.
ECOA
Equal Credit Opportunity Act — federal anti-discrimination law in credit transactions, implemented by Regulation B.
Escrow account
A lender-held account that pays property taxes, insurance, and other recurring property charges from the borrower's monthly payment.
Extension fee
The price hit a borrower pays to extend a rate lock beyond its original expiration.
F
Fallout
Loans that don't close after locking. The complement of pull-through.
FHA loan
Mortgage insured by the Federal Housing Administration, allowing low down payments and flexible credit requirements.
FHA MIP
FHA Mortgage Insurance Premium — the upfront and monthly insurance charged on FHA-insured loans.
FICO score
A credit score (300-850) from Fair Isaac that lenders use as a primary input to risk-based pricing and program eligibility.
FIPS code
Federal Information Processing Standards code identifying U.S. states (2-digit) and counties (5-digit). Stable, federal-canonical geographic key.
Float-down
A lock option allowing a borrower to capture a lower rate if rates fall during the lock period, often for a fee.
G
Gain on sale
The economic gain a lender realizes when selling a closed loan to an investor — the price received above the loan's principal balance plus any servicing value.
GLBA
Gramm-Leach-Bliley Act — federal law including the Safeguards Rule that governs financial institutions' protection of customer information.
H
HMAC (Hash-based Message Authentication Code)
A cryptographic construction that produces a tag from a message and a shared secret, verifiable by anyone with the secret.
HMDA
Home Mortgage Disclosure Act — federal law requiring lenders to report mortgage-application data annually to the FFIEC.
Home Possible
Freddie Mac's affordable lending product analogous to HomeReady, with similar income limits and high-LTV support.
Homeowner's insurance
Property insurance required by lenders to protect collateral; escrowed monthly with mortgage payment in most cases.
HomeReady
Fannie Mae's affordable lending product for low-to-moderate-income borrowers, with reduced mortgage insurance and flexible underwriting.
I
J
L
Lender credit
Money the lender contributes toward a borrower's closing costs in exchange for a higher note rate.
LLPA (Loan-Level Pricing Adjustment)
A pricing adjustment grid keyed by risk attributes (FICO, LTV, occupancy, doc type) applied as basis-point adjustments to base price.
Loan Estimate (LE)
The TRID-mandated three-page form delivered within three business days of application showing estimated terms and costs.
Loan officer compensation
Compensation paid to loan officers, regulated by the LO Compensation Rule (Reg Z) restricting per-loan and dual compensation.
Loan tape
A structured dataset describing closed loans offered for sale to investors — the input to bid-tape execution.
Lock breakage
A scenario where a locked loan doesn't fund and gets cancelled, often re-locked at a different rate.
Lock period
The number of days during which a quoted rate is guaranteed to the borrower, in exchange for a price hit on shorter or longer locks.
LOS
Loan origination system — the system of record for the loan throughout its lifecycle.
LTV (Loan-to-Value ratio)
The ratio of the first-lien loan amount to the property's appraised value, expressed as a percentage.
M
Mandatory delivery
An execution type where the originator commits to deliver closed loans with a breakage fee for non-delivery.
Margin (rate margin)
A markup added to base price by the lender to cover origination cost and contribute to profit. Layered by org, branch, and loan officer.
MBS
Mortgage-backed security — a debt obligation collateralized by a pool of mortgage loans.
Mini-correspondent
A hybrid of broker and correspondent: originates and funds in own name with shorter holding periods than full correspondents.
MISMO 3.4
Mortgage Industry Standards Maintenance Organization version 3.4 — the canonical XML schema for loan applications, used widely by LOS systems.
Mortgage insurance (MI)
Insurance protecting the lender against borrower default, typically required on conventional loans with LTVs above 80%.
MSR
Mortgage-servicing rights — the contractual right to service a closed loan in exchange for a servicing fee.
N
NATS JetStream
Persistent, replayable streaming on top of NATS Core. RateStack's event backbone — every domain event flows through JetStream with idempotent replay.
NMLS
Nationwide Multistate Licensing System — the federal/state licensing registry for mortgage loan originators.
Non-QM
Non-Qualified Mortgage products that fall outside CFPB's Qualified Mortgage rule, often serving self-employed, foreign-national, or DSCR borrowers.
Note rate
The interest rate stated on the promissory note. Distinct from APR, which includes prepaid finance charges.
O
P
Par price
A loan price of 100.000 — the loan balance is paid in full with no premium and no discount.
PII (Personally Identifiable Information)
Information that identifies a specific individual — emails, phones, SSNs, financial account numbers.
POS (Point-of-Sale)
A consumer-facing loan-application portal that initiates the LOS workflow.
Prepayment penalty
A fee charged when a borrower pays off a loan before a specified term — generally prohibited on QM and most consumer mortgages post-Dodd-Frank.
Pricing mode
BEST_EX, BY_RATE, or BY_PRICE — the three execution modes the engine supports for different use cases.
Pull-through
The ratio of locked loans that actually fund — a key input to pipeline hedging.
Q
R
Rate lock agreement
The contract between borrower and lender memorializing the locked rate, lock period, and conditions.
Rate spread
Per HMDA, the difference between the loan's APR and the average prime offer rate (APOR) for a comparable loan, used in fair-lending analysis.
Ratesheet
The grid of (program, rate, price) cells that an investor publishes — typically daily — describing the prices it will pay for closed loans.
Ratesheet version
An immutable snapshot of an investor's pricing grid at a point in time, identified by version id.
Rebate
A loan price above par — the investor pays a premium for the loan, typically passed to the borrower as lender credit or used to offset closing costs.
RESPA
Real Estate Settlement Procedures Act — federal law governing settlement disclosures, kickbacks, and escrow accounts.
RFC 7807 problem details
An IETF standard for HTTP error responses. Returns application/problem+json with type, title, detail, status, instance, and extensions.
S
Scenario
A saved loan profile (borrower, loan, property, transaction, execution) that an LO can rerun against current pricing in one click.
Sell-side pricing
Pricing that returns what an investor would pay for a closed loan — used by lock desks and secondary marketing for bid-tape and execution decisions.
ShedLock
A Java library providing distributed locking on top of databases or Redis. RateStack uses it to ensure scheduled jobs run once across all replicas.
SRP (Servicing Released Premium)
The premium an investor pays for the right to service a closed loan, layered into the price the correspondent receives.
SSO (Single Sign-On)
Authentication via an external identity provider (IdP). RateStack supports Google, Microsoft, and Apple Sign-In; SAML on Enterprise.
SSRF (Server-Side Request Forgery)
An attack class in which untrusted input causes a server to make outbound requests to internal or restricted endpoints.
Stage 1 eligibility
Cheap pre-flight predicate evaluation that filters out programs the borrower cannot take before the full pricing ladder runs.
T
TBA market
To-Be-Announced — the forward market for agency mortgage-backed securities, used heavily for pipeline hedging.
TILA
Truth in Lending Act — federal law requiring disclosure of credit terms and APR; implemented by Regulation Z.
Title insurance
Insurance protecting against title defects discovered after closing; lender's title is required, owner's title is optional.
TRID
TILA-RESPA Integrated Disclosure rule under Regulation Z, governing Loan Estimate (LE) and Closing Disclosure (CD) timing and content.
U
ULAD
Uniform Loan Application Dataset — the GSE-mandated dataset for the redesigned Form 1003, expressed in MISMO 3.4 XML.
ULDD
Uniform Loan Delivery Dataset — the GSE-mandated XML dataset for loan delivery, expressed in MISMO 3.0+ format.
Underwriting overlays
Lender- or investor-specific underwriting requirements stricter than the GSE base guidelines.
USDA loan
Rural housing mortgage guaranteed by the U.S. Department of Agriculture for moderate-income borrowers in eligible rural areas.