Coinbase and GDAX

Missing basis often starts with old Coinbase, Pro, or GDAX history.

Gainz imports Coinbase CSVs and Coinbase Pro/GDAX fills, then helps review converts, transfers, overlapping exports, and sales that still need earlier acquisition basis.

Download Gainz Read Coinbase guide

Gainz Import page showing source files and revision history — Import and data-source review help spot overlapping history and parser warnings.

Review questions

Common Coinbase/GDAX basis gaps.

Old Pro/GDAX fills

Historical fills may live in a different export from Coinbase retail transaction history.

Converts

Convert rows need both sides represented so proceeds and basis are traceable.

Transfers

Transfers between Coinbase products or wallets can hide acquisition context if only one side is imported.

Duplicate files

Full-history and yearly exports can overlap. Gainz surfaces source overlap warnings for review.

Workflow

Use source files, not guesses.

Import Coinbase retail transaction exports.
Import Coinbase Pro/GDAX fills when available.
Review skipped rows, unsupported types, and source overlap warnings.
Declare current holdings and run FIFO only after obvious import gaps are reviewed.
Use the work order and packet status files to hand unresolved basis questions to a CPA.

Not tax advice

Gainz helps organize Coinbase/GDAX records and open questions. It does not decide tax treatment or guarantee complete source history.