> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fincept.in/llms.txt
> Use this file to discover all available pages before exploring further.

# Calculate Implied Repo Rate

> Calculate the implied repo rate from spot and futures prices. The implied repo rate is the break-even financing rate that makes cash-and-carry arbitrage unprofitable. It accounts for the cost of borrowing cash to buy the underlying, income received (dividends/coupons), and storage costs. Used extensively in bond futures trading to identify cheapest-to-deliver bonds and arbitrage opportunities. The difference between implied repo and actual repo rates signals trading opportunities. [Tier: STANDARD, Credits: 2]



## OpenAPI

````yaml api-specs/solver.json post /quantlib/solver/finance/implied-repo-rate
openapi: 3.1.0
info:
  title: FinceptQuantLib API - Solver
  description: >-
    Solver module endpoints for FinceptQuantLib API. The Solver module (Basic
    Tier, 1 credit per request) provides advanced financial solvers including
    bond analytics (yield, duration, convexity), implied volatility
    calculations, spread computations (Z-spread, ASW, OAS), curve bootstrapping,
    interest rate conversions, and model calibration (Vasicek, CIR). Essential
    for fixed income analysis, derivatives pricing, and risk management.
  version: 3.0.0
  contact:
    name: Fincept API Support
    url: https://fincept.in
servers:
  - url: https://api.fincept.in
    description: Fincept API Production Server
security:
  - APIKeyHeader: []
tags:
  - name: quantlib-solver
    description: >-
      Advanced financial solvers for bond analytics, implied volatility, spread
      calculations, and model calibration
    x-displayName: Solver
paths:
  /quantlib/solver/finance/implied-repo-rate:
    post:
      tags:
        - quantlib-solver
      summary: Calculate Implied Repo Rate
      description: >-
        Calculate the implied repo rate from spot and futures prices. The
        implied repo rate is the break-even financing rate that makes
        cash-and-carry arbitrage unprofitable. It accounts for the cost of
        borrowing cash to buy the underlying, income received
        (dividends/coupons), and storage costs. Used extensively in bond futures
        trading to identify cheapest-to-deliver bonds and arbitrage
        opportunities. The difference between implied repo and actual repo rates
        signals trading opportunities. [Tier: STANDARD, Credits: 2]
      operationId: implied_repo
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
                - spot
                - futures
                - time_to_expiry
              properties:
                spot:
                  type: number
                  description: Current spot price
                  example: 100
                futures:
                  type: number
                  description: Futures price
                  example: 102
                time_to_expiry:
                  type: number
                  description: Time to futures expiry in years
                  example: 0.25
                income:
                  type: number
                  description: >-
                    Present value of income (dividends, coupons) received during
                    holding period
                  default: 0
                  example: 0.5
                storage_cost:
                  type: number
                  description: >-
                    Present value of storage/carrying costs during holding
                    period
                  default: 0
                  example: 0.1
            example:
              spot: 100
              futures: 102
              time_to_expiry: 0.25
              income: 0.5
              storage_cost: 0.1
      responses:
        '200':
          description: Successful Response
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                    example: true
                  data:
                    type: object
                    properties:
                      implied_repo_rate:
                        type: number
                        description: The implied repo rate as a decimal
                        example: 0.064
              example:
                success: true
                data:
                  implied_repo_rate: 0.064
        '401':
          $ref: '#/components/responses/UnauthorizedError'
        '402':
          $ref: '#/components/responses/InsufficientTierError'
        '422':
          description: Validation Error
          content:
            application/json:
              schema:
                type: object
                properties:
                  detail:
                    type: array
                    items:
                      type: object
      security:
        - APIKeyHeader: []
components:
  responses:
    UnauthorizedError:
      description: Authentication information is missing or invalid
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: string
                example: Invalid API key
    InsufficientTierError:
      description: API tier insufficient for this endpoint
      content:
        application/json:
          schema:
            type: object
            properties:
              detail:
                type: string
                example: Endpoint requires Basic tier or higher
  securitySchemes:
    APIKeyHeader:
      type: apiKey
      in: header
      name: X-API-Key
      description: >-
        API key for authentication. Get your key at
        https://api.fincept.in/auth/register

````