Finding a historical OHLCV record may be easy.
Tax and Accounting
Historical Market Data for Tax and Accounting Workflows
Tax calculations, portfolio valuations, reconciliations, and financial reporting often require market data from specific historical periods.
FinFeedAPI Flat Files S3 API provides bulk access to historical OHLCV datasets through an S3-compatible interface, with GZIP-compressed CSV files using the documented Flat Files schema and organized by supported exchange, available OHLCV period, and date. Teams can use this data as an input to their own valuation, accounting, and reporting methodologies.
A Historical Value Needs More Than a Number
Biggest Pain Points
Historical valuations need a defined market-data source
Using different sources across calculations can create inconsistent inputs.
The same market period contains multiple values
OHLCV records include open, high, low, close, and volume. The appropriate input depends on the organization's methodology.
Older periods can involve substantial data collection
Historical reconciliation or backdated reporting may require data covering many dates.
Manual market-data lookups are difficult to scale
Looking up individual historical observations across spreadsheets, websites, or separate systems adds repetitive work.
Market data is only one part of the calculation
Accounting treatment, valuation rules, transaction records, tax methodology, adjustments, and jurisdiction-specific requirements still need to be applied separately.
Define the Market Data Behind the Calculation
Consider a valuation that requires historical market information.
The calculation should define more than the date.
InstrumentWhich security or asset is being valued?
ExchangeWhich supported exchange provides the relevant market data?
DateWhich historical date or reporting period applies?
OHLCV periodWhich available aggregation period is appropriate?
Price fieldDoes the organization's methodology use open, high, low, close, or another calculation based on the available data?
Accounting ruleHow is that market-data input incorporated into the final valuation?
FinFeedAPI supplies historical OHLCV data.
Available files and observations depend on supported exchanges, trading calendars, holidays, and available OHLCV periods.
How Does FinFeedAPI Solve It?
Retrieve Historical OHLCV in Bulk
Instead of collecting historical observations through many paginated REST API calls or performing individual lookups, teams can retrieve date-partitioned historical files through S3-compatible operations such as LIST and GET. This is useful when accounting or reconciliation work spans many historical dates.
Organize Data by Market, Period, and Date
Flat Files are organized by supported exchange, available OHLCV period, and date.
That gives internal systems a defined way to identify the market-data files used for a particular workflow.
A path can follow a structure such as s3://finfeedapi/E-IEXG/T-OHLCV+TP-1MIN/D-20260102.csv.gz
Work With GZIP-Compressed CSV
Historical OHLCV data is delivered as GZIP-compressed CSV files using the documented Flat Files schema. The format can be processed by databases, accounting pipelines, reporting systems, spreadsheets, and analytical environments.
Build Repeatable Retrieval Rules
Accounting systems can define how they select historical files based on supported exchange, available period, and date. The same retrieval logic can then be applied across recurring valuation or reporting workflows.
Keep Market Data Separate From Accounting Logic
FinFeedAPI provides the historical market-data input.
Organizations can keep their own valuation rules, tax treatments, adjustments, rounding, accounting policies, and reporting calculations in a separate processing layer.
This makes the role of the market-data source clearer.
Use Historical Data Where the Calculation Requires It
Historical Portfolio Valuation
Retrieve OHLCV data for relevant historical periods and use the appropriate field or derived calculation according to the organization's valuation methodology.
Period-End Reporting
Collect available historical data corresponding to defined reporting periods and feed selected market-data inputs into financial reporting processes.
Available observations depend on exchange trading calendars, holidays, and the selected OHLCV period.
Historical Reconciliation
When an old valuation or report needs to be investigated, retrieve market data corresponding to the relevant supported exchange, period, and date and compare it with the inputs recorded internally.
Capital Gains Workflows
Historical OHLCV can provide market-data context for tax calculations where historical market values are required.
Cost basis, transaction prices, acquisition and disposal records, tax-lot methodology, fees, corporate actions, and applicable tax rules require separate data and logic.
Backdated Accounting Reviews
Bulk file access can help when a team needs historical market data across many dates rather than one isolated lookup.
Internal Valuation Archives
Organizations can download and retain permitted historical files within their own data infrastructure according to applicable licensing and data-management requirements.
This allows the market-data component to sit alongside transaction records, calculation outputs, and other accounting evidence.
Match the Data to the Valuation Workflow
| Flat Files Capability | Accounting Application | Example |
|---|---|---|
| Historical OHLCV | Historical valuation inputs | Access open, high, low, close, and volume data for historical periods |
| Available OHLCV Periods | Valuation methodology | Select an available aggregation period appropriate to the calculation |
| Supported Exchange Organization | Market-source definition | Identify which supported exchange dataset is being used |
| Date Partitioning | Period-specific retrieval | Identify files corresponding to relevant historical periods |
| GZIP-Compressed CSV | Accounting data processing | Load .csv.gz files using the documented Flat Files schema |
| S3-Compatible Access | Historical data retrieval | Use compatible tools and SDKs with LIST, HEAD, and GET operations |
| Object Listing | File discovery | Identify available objects before retrieval |
| Object Information | Data management | Inspect standard object information such as key, modification time, and size where available |
FinFeedAPI provides historical market data. It does not determine the appropriate accounting value, tax treatment, fair value methodology, cost basis, reporting policy, or regulatory treatment for a transaction or asset.
From Manual Lookups to Defined Historical Data Inputs
| Tax & Accounting Workflow | Before | After With Flat Files S3 API |
|---|---|---|
| Historical market data | Teams may collect observations from spreadsheets, websites, or separate data sources | Historical OHLCV is available through a defined Flat Files dataset |
| Date-based retrieval | Individual historical observations may require repeated manual lookup | Date-partitioned files support systematic historical retrieval |
| Market-source definition | The source behind a historical value may be difficult to reconstruct | Supported exchange, period, and date can be recorded with the data workflow |
| Large historical periods | Backdated reviews require repeated individual retrieval | Historical partitions can be collected in batches through S3-compatible operations |
| Data format | Inputs can arrive in different formats | Flat Files use a documented GZIP-compressed CSV format |
| Recurring calculations | Teams repeat the same data-gathering process each period | File-selection and retrieval rules can be incorporated into recurring pipelines |
| Historical reconciliation | Teams search manually for market data related to an old calculation | Relevant historical files can be identified using the original market-data scope |
| Accounting integration | Market data and valuation logic may be mixed into manual processes | Historical OHLCV can feed a separate accounting or valuation processing layer |
Connect Historical Market Data to Existing Systems
S3-Compatible Access for Historical Retrieval
FinFeedAPI provides an S3-compatible interface for discovering and retrieving Flat Files.
Teams can use operations such as LIST, HEAD, and GET with compatible tools, SDKs, and internal applications.
GZIP-Compressed CSV for Data Processing
Historical OHLCV files are delivered as GZIP-compressed CSV using the documented Flat Files schema.
They can be decompressed and processed before being loaded into databases, valuation engines, reporting systems, or other accounting infrastructure.
Object Listing for Historical Discovery
Systems can list available prefixes and objects to identify historical files corresponding to the required supported exchange, OHLCV period, and date.
File and observation availability depends on supported exchanges, trading calendars, holidays, and available OHLCV periods.
Internal Storage for Accounting Records
Organizations can incorporate downloaded data into their permitted internal storage workflows, subject to applicable licensing and data-use terms.
Their own systems can then associate relevant market-data inputs with transaction records, valuation calculations, reporting periods, or other accounting records.
Keep the Market-Data Input Traceable
A historical valuation workflow can follow a defined sequence:
RequirementDetermine why historical market data is needed.
InstrumentIdentify the asset or security.
MarketSelect the supported exchange according to the organization's methodology.
DateDetermine the applicable historical date or reporting period.
PeriodSelect an available OHLCV period.
RetrieveIdentify and download the corresponding .csv.gz file where available.
CalculateApply the organization's selected price field, calculation, adjustments, and valuation methodology.
RecordStore the relevant market-data reference alongside the organization's calculation and supporting records.
ReviewRevisit the market-data input when a historical calculation needs to be investigated or reproduced.
FinFeedAPI can make the historical market-data component easier to identify and retrieve.
Build Historical Market Data Into Your Accounting Workflow
Use historical OHLCV Flat Files instead of relying on repeated manual market-data lookups. Define the supported exchange, available OHLCV period, and historical range, retrieve the corresponding available files through an S3-compatible interface, and apply your organization's valuation or accounting methodology downstream.
FinFeedAPI Flat Files S3 API provides a structured historical market-data layer for valuations, reconciliations, period-end reporting, backdated reviews, and other tax and accounting workflows.