Trade Records and Tax Calculation Tools

If you cannot prove your cost basis, tax authorities assume the entire proceeds are profit. Without records, you pay tax on money you never made — and you cannot undo it later.

Records are not bureaucracy. They are your only defense at audit and the input to every tax calculation.

What to record per trade

A complete trade record contains:

Field	Why it matters
Date and time	Determines holding period
Instrument / ticker	Identifies the asset
Side (buy/sell)	Pairs into tax lots
Quantity	Scales the gain
Price	Drives proceeds and basis
Fees and commissions	Add to basis / reduce proceeds
Account	Matches broker reports
Realized P&L	Confirms the taxable event

Reconcile with broker reports

Brokers issue year-end reports (Form 1099-B in the US, contract notes everywhere). Your records must match these. Discrepancies usually arise from:

• Adjusted cost basis after corporate actions (splits, mergers)
• Wash sale adjustments the broker applied
• Forex conversion on foreign-listed shares
• Transfers between brokers losing the cost-basis chain

Reconcile quarterly, not annually. Waiting until April guarantees pain.

Tools by instrument

Need	Tool type
Stocks, options, futures	TradeLog, GainsKeeper, Excel
Crypto	Koinly, CoinTracker, Coinpanda, ZenLedger
Forex	Broker reports plus dedicated trader software
Multi-asset	TradeLog, TraderSync (journals)

Dedicated software wins when you trade across many instruments or hundreds of transactions a year. A spreadsheet suffices for low-volume investors.

Spreadsheet template basics

Minimum columns: Date, Symbol, Side, Qty, Price, Fee, Account, Lot ID, Notes. Add a "holding period" column computed from buy and sell dates. Add a "wash sale flag" to surface disallowed losses before year-end.

Retention periods

Jurisdiction	Keep records for
US	At least 7 years; indefinitely for cost basis
UK	5 years and 10 months after the tax year
Canada	6 years from end of tax year
Australia	5 years

Keep digital copies in at least two locations. Broker statements disappear when you close accounts — export them first.

Practical steps

1. Record every trade the day it happens — memory is not a record
2. Reconcile against broker reports quarterly
3. Track wash sales / superficial losses in real time, not at year-end
4. Export broker statements before closing an account
5. Back up records in two locations

Bottom line

The taxman presumes profit when records are missing. Good records turn a year-end panic into a fifteen-minute task.