Specific identification when fills arrive in fragments

Partial closes and iceberg-style fills make lot selection harder. A practical way to keep identification defensible.

Specific identification only helps if your records show which acquisition lot you intended to close. High-volume cryptocurrency traders rarely get a single clean fill against a single resting lot. Venues return fragments; you scale out across sessions; fees shave quantities.

Keep a contemporaneous note

When you mean to close a particular high-basis lot, record the lot ID or acquisition timestamp in your desk log the same day. After-the-fact storytelling is weaker when an adviser or auditor asks why that lot was chosen.

Handle fragments consistently

Decide whether fragments from one order share a single disposition event or are matched FIFO within the day. Consistency matters more than cleverness. Document the rule in the engagement letter for any third-party review.

Fee rows

Maker rebates and taker fees change net quantities. Import fee rows with the fills; do not back into fees from a monthly invoice if the venue provides per-fill detail.

Crypto Portfolio Desktop can store lot IDs between sessions; a formal Tax-Lot Performance Review still verifies that the IDs line up with exchange exports before anyone relies on the schedule for filing conversations.