Term · Automated Customer Account Transfer Service

ACATS

Published May 9, 2026

Definition

ACATS — the Automated Customer Account Transfer Service — is a DTCC-operated electronic system that standardizes the transfer of customer brokerage accounts between firms. It handles full and partial transfers, preserves lot-level cost basis and acquisition dates via the Cost Basis Reporting Service, and settles in a typical 5–7 business-day window.

ACATS exists because account transfers used to be paper-and-fax-based bilateral processes that took weeks and routinely lost lot-level cost-basis data. DTCC built ACATS in the 1980s as a standardized inter-firm messaging system and has expanded it since to handle the full diversity of modern brokerage accounts: cash, margin, IRAs, qualified plans, trust accounts, custodial accounts, and the lot-level basis that the IRS's covered-securities rules now require firms to track.

The flow is initiated by the receiving firm, which sends a Transfer Initiation Form (TIF) to DTCC referencing the delivering firm's DTC number, the customer's account at the delivering firm, and the transfer scope (full or partial, with itemized assets if partial). The delivering firm has 1 business day to validate and accept (or reject with one of ~20 standard codes), then 3-5 business days to prepare the assets, then settlement on T+5 to T+7. Securities move via DTC; cash moves via FedWire or ACH; lot-level basis moves via CBRS as a separate post-settlement transmission.

For wealth-tech platforms, ACATS is the rail that handles new-account funding, account migration, and cross-firm consolidation. Most platforms underestimate the integration surface — partial transfers, fractional-share residuals, transfer-during-corporate-action edge cases, and the rejection-and-resubmit flow are all part of the ACATS reality and all routinely produce production bugs that mock data hides. The 96-month longitudinal data in the [WealthSynth catalog](/datasets) includes realistic ACATS history for ~8% of households as part of the integration-testing surface.

T+0
Receiving firm submits TIF to DTCC
Transfer Initiation Form references delivering firm's DTC number, customer's account, and transfer scope (full/partial).
T+1
Validation / acceptance
Delivering firm accepts or rejects with one of ~20 standard codes (SSN mismatch, account-type mismatch, prior pending, etc.).
T+2 to T+4
Review and prepare
Delivering firm prepares assets; account is partially frozen; corporate actions during this window have to be handled per record date.
T+5 to T+7
Settlement
Securities move via DTC; cash via FedWire/ACH; lot-level basis via CBRS.

Why this matters for synthetic data

ACATS-aware synthetic data needs lot-level basis with `transfer_history` provenance — a lot that was transferred in via ACATS retains its original acquisition date and basis, with the receiving firm carrying the migration trail. Realistic test corpora include both successful transfers and rejection-resubmit sequences, partial transfers with fractional residuals, and at least some transfers that intersect with corporate-action ex-dates during the settlement window. A test corpus that ships only full-transfer happy-path scenarios has not exercised the cases where ACATS bugs actually hide.

Common pitfalls

Re-clocking lot acquisition dates at the transfer date — transferred lots preserve original acquisition date and holding-period clock; re-clocking flips long-term lots to short-term and is a tax bug.
Assuming partial transfers transfer exact share counts — fractional residuals are typical and produce cash-in-lieu liquidations that have to be reconciled separately.
Treating the settlement window as instantaneous — corporate actions during settlement have to be assigned to delivering or receiving firm based on record date.
Not handling rejection codes — ~3-5% of transfers are rejected on first submission; platform's resubmit flow has to be tested.

Examples

Partial transfer with fractional residual

Customer requests transfer of 150 shares of VTI from delivering account holding 150.34 shares. Delivering firm transfers 150 shares (lot acquisition dates and basis preserved via CBRS) and liquidates the 0.34-share residual at the post-transfer market price, with cash settling separately. The receiving firm reflects 150 shares with original lot data; the cash component arrives 1-2 business days after the securities.

Frequently asked questions

How long does an ACATS transfer take?+

Typically 5-7 business days from initiation to settlement. The 1-business-day validation window is fixed; the 3-5 business-day review-and-prepare window is where most of the variability sits. Transfers involving non-covered lots (pre-2011 acquisitions) or alternative investments can take longer because basis reconciliation requires manual research.

What does ACATS not handle?+

Alternative investments held outside DTC (private funds, direct real estate, certain insurance products) typically can't transfer via ACATS and require bilateral processing. Cryptocurrency holdings (in firms that custody crypto) generally aren't ACATS-eligible. Non-US accounts are outside ACATS scope. Transfers within the same firm but between different account types are typically internal journal entries rather than ACATS transactions.

What happens to lot-level basis if it doesn't transfer cleanly?+

The receiving firm reflects the lot with placeholder basis (often $0 or the transfer-date market price) pending manual reconciliation. The customer can supply documentation (old confirmations, statements, tax forms) to establish the correct basis; the receiving firm updates the record and re-files corrected 1099-B if a sale has already occurred at incorrect basis. This reconciliation flow is a real customer-experience pain point and one of the ACATS edge cases test data has to exercise.