Days 0–30 · Mobilize & baseline

Governance & baseline

Name a single accountable TSA exit owner on the buyer side and a steering committee with the seller.
Inventory the full service catalog: every service, owner, dependency, SLA, and end date.
Baseline current monthly TSA cost by service family and model extension-fee exposure week by week.
Build the master exit plan with dated milestones and a critical-path view across workstreams.
Set the reporting cadence, RACI, and escalation path before the first cutover decision.
Confirm exit-ramp terms, notice windows, and termination mechanics in the TSA itself.

Days 31–60 · Build & execute by workstream

IT separation

Sequence network, identity (AD/SSO), email/domain, endpoint, and application cutovers by dependency.
Stand up the target environment; migrate and validate data with reconciliation sign-off.
Plan parallel-run windows for high-risk systems; define rollback for each cutover.
Map and re-paper third-party licenses and contracts moving to NewCo.

Finance separation

Cut over GL, AP/AR, and the fixed-asset register; agree the close calendar through transition.
Stand up banking, treasury connectivity, and payment controls for Day One independence.
Validate every TSA invoice against the catalog; dispute overcharges in the period they occur.

HR & payroll separation

Establish payroll (domestic and international), tax registrations, and benefits enrollment.
Migrate HRIS, time & attendance, and the ATS; confirm 401(k)/pension administration.

Procurement & vendors

Reassign or renegotiate vendor contracts; rebuild the procurement catalog and P2P flow.
Onboard suppliers to NewCo; confirm EDI/trading-partner cutovers.

Days 61–90 · Cut over & decommission

Cutover, validate, terminate

Run go/no-go gate reviews; execute cutovers against the runbook with hypercare on standby.
Validate each function operates independently; capture sign-off from the service owner.
Formally terminate each service in writing as it exits, to stop the fee meter immediately.
Deprovision retained access and decommission the seller environment and licenses.
Reconcile final TSA invoices, true-ups, and any credits owed.
Run a lessons-learned review and confirm zero stranded costs before closeout.

This checklist is a starting framework, not a substitute for a deal-specific exit plan. Real timelines depend on system complexity, data quality, and seller cooperation. See typical duration by function →

The 90-day TSA exit checklist.