> ## Documentation Index > Fetch the complete documentation index at: https://developer.hayinsights.com/llms.txt > Use this file to discover all available pages before exploring further. # BOJ ETF holdings history > Monthly Bank of Japan ETF holdings (trillion JPY) next to the size of the Japanese ETF market (JITA, 100 million JPY) and the BOJ's share of it, with annotations on key policy changes. Defaults to the last ten years. ## OpenAPI ````yaml /openapi.yaml get /openapi/v1/etf/boj-holdings openapi: 3.1.0 info: title: HayInsights Open API version: 0.1.0 description: > Programmatic access to the **HayInsights** financial-data hub — commodities, crypto, ETF, FX, macroeconomic, real-estate, news, economic-calendar and market-index datasets, served from a single API surface under `/openapi/v1/*`. This specification is the **single source of truth** for the public API surface — shared by SDK codegen, the reference docs, and (later) the mock server / contract tests. ## Authentication Every request must carry your API key in the `X-API-Key` header. There is a single authentication tier — no request signing. Create and manage keys in the HayInsights dashboard (Account → API keys). See **Authentication**. ## Plans & quota Access to each data domain and your request quota are governed by the subscription plan attached to your key. Each endpoint consumes a **weighted** amount of your per-minute quota; every response carries `X-RateLimit-*` headers. See **Rate limits** and **Plans & features**. contact: {} servers: - url: https://api-v2.hayinsights.com description: Production security: - HayInsightsApiKey: [] tags: - name: Commodities description: >- Spot prices, top movers, gold–DXY correlation and historical series for energy, metals and agricultural commodities. - name: Crypto description: >- Crypto market overview, dominance, bubble map, on-chain and derivatives metrics. - name: ETF description: >- Exchange-traded fund listings, performance & net-flow rankings, heatmap, holdings, NAV growth, fund composition and Bank of Japan ETF holdings. - name: FX description: >- Foreign-exchange summary, live table, 90-day correlation matrix and the emerging-market stress monitor. - name: Macro description: >- Macroeconomic indicators — GDP, CPI/PCE, exchange rates, population, central-government debt, policy rates / bond yields, interbank rates, FDI and trade by region. - name: Real Estate description: >- Land prices, transaction-level records, administrative geography (provinces / wards) and choropleth GeoJSON, by country. - name: News description: >- Market news headlines with per-article sentiment, plus an aggregate sentiment reading over a rolling window. - name: Calendar description: >- Economic calendar — rate decisions, CPI and GDP releases, market holidays and asset-level events. - name: Market description: >- Index snapshots and global index closes — levels and daily moves for S&P 500, Nasdaq, Nikkei, VN-Index and others. - name: Equities description: >- Japanese stock detail (Tokyo Stock Exchange) — end-of-day snapshot, corporate events, daily prices, financial statements and sector peers. paths: /openapi/v1/etf/boj-holdings: get: tags: - ETF summary: BOJ ETF holdings history description: > Monthly Bank of Japan ETF holdings (trillion JPY) next to the size of the Japanese ETF market (JITA, 100 million JPY) and the BOJ's share of it, with annotations on key policy changes. Defaults to the last ten years. operationId: etfBojHoldings parameters: - name: from in: query required: false description: Start month (YYYY-MM). schema: type: string pattern: ^\d{4}-(0[1-9]|1[0-2])$ example: 2016-01 - name: to in: query required: false description: End month (YYYY-MM). schema: type: string pattern: ^\d{4}-(0[1-9]|1[0-2])$ example: 2026-09 responses: '200': description: Monthly BOJ ETF holdings. content: application/json: schema: $ref: '#/components/schemas/EtfBojHoldingsResponse' example: success: true statusCode: 200 data: - month: 2024-02 holdingsCho: 37.2 totalMarketOku: 1135000 bojPctOfMarket: 32.8 - month: 2024-03 holdingsCho: 37.2 totalMarketOku: 1182000 bojPctOfMarket: 31.5 annotation: month: 2024-03 label: BOJ ends ETF purchases meta: timestamp: '2026-10-16T04:00:00.000Z' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' '429': $ref: '#/components/responses/RateLimited' '500': $ref: '#/components/responses/InternalError' components: schemas: EtfBojHoldingsResponse: allOf: - $ref: '#/components/schemas/EnvelopeBase' - type: object required: - data properties: data: type: array items: type: object required: - month - holdingsCho properties: month: type: string description: Month (YYYY-MM). example: 2024-03 holdingsCho: type: - number - 'null' description: BOJ ETF holdings, trillion JPY. example: 37.2 totalMarketOku: type: - number - 'null' description: Total ETF market net assets, 100 million JPY. example: 1182000 bojPctOfMarket: type: - number - 'null' description: BOJ holdings as % of the ETF market. example: 31.5 annotation: type: object description: Present on months with a key policy change. properties: month: type: string description: Month. example: 2024-03 label: type: string description: Policy event. example: BOJ ends ETF purchases EnvelopeBase: type: object description: > Standard success envelope shared by every endpoint. Each operation's response wrapper extends this (via `allOf`) and adds a typed `data` property. required: - success - statusCode properties: success: type: boolean const: true description: Always `true` for a successful response. example: true statusCode: type: integer description: Mirrors the HTTP status code. example: 200 meta: $ref: '#/components/schemas/Meta' ErrorBody: type: object description: Standard error envelope returned for every 4xx / 5xx response. required: - success - statusCode - error properties: success: type: boolean const: false description: Always `false` for an error response. example: false statusCode: type: integer description: Mirrors the HTTP status code. example: 401 error: $ref: '#/components/schemas/ErrorDetail' meta: $ref: '#/components/schemas/Meta' Meta: type: object description: >- Response metadata. Always present; `timestamp` is the server time the response was generated. required: - timestamp properties: timestamp: type: string format: date-time description: Server time when the response was generated (ISO 8601). example: '2026-06-19T08:31:59.478Z' additionalProperties: true ErrorDetail: type: object description: Error detail object carried under `error` in the error envelope. required: - code - message properties: code: type: string description: > Machine-readable error code. Specific for authentication / quota errors (e.g. `API_KEY_REQUIRED`, `API_KEY_INVALID`, `FEATURE_NOT_IN_PLAN`, `RATE_LIMIT_EXCEEDED`). For validation (400) and not-found (404) the code is currently `INTERNAL_ERROR` and the HTTP status carries the semantics. example: API_KEY_INVALID message: description: Human-readable message, or a list of validation messages (400). oneOf: - type: string - type: array items: type: string example: Invalid API key responses: BadRequest: description: >- Invalid or missing parameter — bad enum, range, format, or a missing required query parameter. content: application/json: schema: $ref: '#/components/schemas/ErrorBody' example: success: false statusCode: 400 error: code: INTERNAL_ERROR message: - >- Invalid type parameter. Must be "gdp", "cpi", "pce", or "import-export" - Type parameter is required meta: error: Bad Request statusCode: 400 timestamp: '2026-06-19T08:34:08.081Z' Unauthorized: description: >- Missing, invalid, disabled or expired API key. Send a valid key in the `X-API-Key` header. content: application/json: schema: $ref: '#/components/schemas/ErrorBody' example: success: false statusCode: 401 error: code: API_KEY_INVALID message: Invalid API key meta: timestamp: '2026-06-19T08:34:08.023Z' Forbidden: description: >- Your subscription plan does not include this data feature, or your key's scope denies it. content: application/json: schema: $ref: '#/components/schemas/ErrorBody' example: success: false statusCode: 403 error: code: FEATURE_NOT_IN_PLAN message: Your plan does not include this feature meta: timestamp: '2026-06-19T08:34:08.100Z' RateLimited: description: > Rate limit exceeded — you have consumed your plan's per-minute weight budget. Wait until `X-RateLimit-Reset` (or `Retry-After` seconds) then retry. headers: X-RateLimit-Limit: $ref: '#/components/headers/XRateLimitLimit' X-RateLimit-Remaining: $ref: '#/components/headers/XRateLimitRemaining' X-RateLimit-Reset: $ref: '#/components/headers/XRateLimitReset' X-RateLimit-Weight-Used: $ref: '#/components/headers/XRateLimitWeightUsed' Retry-After: $ref: '#/components/headers/RetryAfter' content: application/json: schema: $ref: '#/components/schemas/ErrorBody' example: success: false statusCode: 429 error: code: RATE_LIMIT_EXCEEDED message: Rate limit exceeded meta: timestamp: '2026-06-19T08:34:09.000Z' InternalError: description: Unexpected server error. Retry after a short exponential backoff. content: application/json: schema: $ref: '#/components/schemas/ErrorBody' example: success: false statusCode: 500 error: code: INTERNAL_ERROR message: Internal server error meta: timestamp: '2026-06-19T08:34:10.000Z' headers: XRateLimitLimit: description: Your plan's request-weight budget per 1-minute window. schema: type: integer example: 1000 XRateLimitRemaining: description: Remaining request weight in the current 1-minute window. schema: type: integer example: 997 XRateLimitReset: description: Unix timestamp (seconds) when the current rate-limit window resets. schema: type: integer format: int64 example: 1781857979 XRateLimitWeightUsed: description: Request weight consumed by this call (see each endpoint's weight). schema: type: integer example: 3 RetryAfter: description: Seconds to wait before retrying. Present on 429 responses. schema: type: integer example: 30 securitySchemes: HayInsightsApiKey: type: apiKey in: header name: X-API-Key description: > Your HayInsights API key (prefixed `apk_`). Create and manage keys in the HayInsights dashboard (Account → API keys). Send it in the `X-API-Key` header on **every** request to `/openapi/v1/*`. Which data domains you may access and your request quota are both governed by the subscription plan attached to the key — see the **Plans & features** and **Rate limits** guides. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.