DTCC has set 1 February 2027 for decommissioning ACATS legacy fixed and variable files, extending the October 2026 target described in its 2025 transformation announcement. Firms still using the formats must complete migration before that cutoff, including the connections needed to submit transfer instructions and receive the resulting messages.[1][2][3]
The current integration guidance distinguishes the two directions: JSON input is available through API or message queue, while output uses MQ. An API submission build therefore still needs an output arrangement to consume status, settlement, rejection and other messages in the transfer workflow.[1]
What changes in the client interface
Legacy transfer files versus modern messaging
| Feature | Legacy route | Modern route |
|---|---|---|
| Format | Fixed and variable files | JSON standard messagesSource 1 |
| Transport | Batch-style legacy transmission | API or MQ for input; MQ for output under current guidanceSource 1Source 2 |
| Processing potential | Established ACATS workflow | More extensible workflows, stronger resiliency and scope for real-time processingSource 3 |
| New functionality | No new features planned for legacy formats | New features are added to the modern formats, including 529-plan transfer supportSource 3Source 1 |
| End date | Decommissioned after the migration | 1 February 2027 deadline for firms still using legacy filesSource 1Source 2 |
DTCC’s API Marketplace supplies the APIs, schemas and starter kit. Access requires the firm’s Super Access Coordinator to enable the appropriate entitlement. Its published integration steps include connection setup, testing, sign-off and production implementation; firms using a service bureau or vendor need to establish which of these steps and message types the provider covers.[1][3]
The transfer cycle was already shortened separately
ACATS operating context
| Measure | Value | Context |
|---|---|---|
| Service operator | NSCC, a DTCC subsidiary | ACATS standardises account and asset transfers among broker-dealers, banks and other participants.Source 4Source 3 |
| Standard full-transfer cycle before the 2025 change | About 4–5 business days | Manual exceptions and asset-specific issues could take longer.Source 3 |
| Cycle after the one-day reduction | About 3–4 business days | The production change followed the move to T+1 settlement and aligned mutual funds and options with other securities.Source 3 |
| Asset coverage | Broad, but not universal | ACATS supports equities, bonds, funds, options, annuities, alternatives and cash; actual transferability still depends on the asset and receiving firm.Source 4 |
The earlier cycle reduction came from removing a processing stage. DTCC says transfers first stopped moving into the end-of-day Settle Prep status on 17 October 2025; the final Fund/SERV Day 2 acknowledgment was received on 20 October. That workflow change and the JSON interface migration are separate improvements.[1][3]
Account transfer completion still involves validation by the delivering and receiving firms, settlement of eligible positions and handling exceptions. Investors continue to initiate transfers through the receiving firm. Residual cash, non-transferable assets, tax lots and account-registration differences can require further work even when messages move promptly between systems.[4][3]
The operational test before February is whether the full instruction-and-response flow works across each firm and its providers. After migration, rejected transfers, manual status enquiries and delays caused by incomplete information will be useful measures of the customer benefit.[1][3]
Sources & further reading
- ACATS client-interface modernisation and 2027 release DTCC Learning · Accessed 16 Oct 2026
- ACATS modernisation resources and legacy-file decommission notice DTCC Learning · Accessed 16 Oct 2026
- ACATS transformation: shorter cycle and modern interfaces DTCC · 16 Sep 2025 · Accessed 16 Oct 2026
- Automated Customer Account Transfer Service overview DTCC · Accessed 16 Oct 2026