Deals fail
Do the no-regret work first.
A deal can be terminated before it closes. Plan so the first months of work pay off either way: data quality, credential standards, the routing rules.
Merger and acquisition integration
Integrating an acquired bankon the deal's timeline.
The clock started before the announcement. The median bank deal now closes in 4-6 months, and the conversion follows by 5-6 months. Customers judge the deal on the first day they bank with you. We support acquirers with technology strategy, architecture, design, data mapping, conversion, reconciliation, and execution.
Two day ones
Every merger has a legal day one and a customer day one.
Most of the integration risk sits in the months between the two, and most of what customers experience happens on the latter.
| Legal day one | Customer day one | |
|---|---|---|
| What happens | The deal closes; the acquired bank becomes part of the acquirer | Systems, brand, accounts and credentials convert |
| What customers see | Little: the same logins, cards and branches | New logins, tokens, cards, statements and often account numbers |
| Customer data | Shared freely from here; before it, only what clean rooms allow | Converted, reconciled and kept for audit |
| The risk | Deposits and relationship managers start to move | Every unresolved problem becomes visible at once |
| Ready by then | The conversion plan, the routing rules and the notice calendar | Mocks, dress rehearsals, preview and a runbook rolled up across every platform |
The program
The conversion is one workstream of many.
An integration runs on the deal's calendar and the acquired bank's contracts, with customers watching from the day it's announced.
Integration management
One office, one plan and one set of readiness gates, with each decision logged.
Customer retention
High-value relationships secured before conversion, when the intent to switch peaks in the months after announcement.
Notices and communication
A calendar fixed by law and a message plan for every segment, from consumers to treasury clients.
Brand, branches and ATMs
Signage, consolidations and closings, each with its own notice period.
Cards and credentials
Card reissue, token issuance and sign-in standards, on the critical path to customer day one.
Vendor exits
Deconversion on the acquired bank's contracts, notice periods and fees, and vendors' calendars for test files.
People
Staffing the conversion while running both banks, and keeping the acquired bank's people who know its systems.
Approvals and conditions
Regulatory approvals, their conditions, and the commitments made to win them.
Synergy tracking
The savings the deal promised, tied to the systems that have to retire to deliver them.
The merger conversion
A merger conversion runs in seven steps, reconciled at each one.
The stages of any conversion apply, and a merger adds two steps: enrichment, which adds the lookups and cross-references the targets need, and segmentation, which routes each client of the acquired bank to one or more of the acquirer's platforms.
- 01DeconversionThe acquired bank's data out of its vendors' platforms, on their utilities and calendars, where a utility exists at all.
- 02StagingEverything landed in a conversion data store, kept afterwards as the original record for audit and legal needs.
- 03EnrichmentThe staged data augmented with lookup and cross-reference data the targets need, such as the new account numbers where accounts are renumbered.
- 04SegmentationEach client and profile routed to its target platforms by rules the business can change, with every decision explained.
- 05TransformationEach target's data model, credential standards and entitlements applied, mapping by mapping.
- 06LoadInto every target, often on the same weekend, in the order the runbook sets.
- 07ReconciliationOut of band at every step, owned by the business as well as technology, with a list of every record dropped and why.
The core conversion guide The commercial treasury conversion guide How we reconcile
Routing, identity and preview
Clients and users don't map one to one.
Merger conversions of commercial and small business clients most often go wrong on routing, identity and preview. We've learned to build for all three.
Routing
Rules held outside the code
A decision engine that routes each profile to its targets, with rules held where the business can change them.
Overrides, audited
White-glove changes arrive up to the final minutes. Each is recorded, with who made it and why.
Profiles with no common key
The same client on two legacy platforms may not be matchable at all. Find out early.
Identity
The acquirer's standards
Unique emails, login formats and phone numbers on file, which means data clean-up that has to finish before day one.
Tokens before day one
Every user who needs one issued in advance, working on both banks' systems through the preview.
Single sign-on for each service
Remote deposit, lockbox, file transfer, cards, bill pay, foreign exchange: each connected service needs its own path.
Preview
A preview before conversion
Clients sign in, reset credentials, download tokens, check entitlements and build templates, without moving money.
After preview, fixes go client by client
Once dual maintenance begins, bulk fixes are no longer possible. Whatever is wrong then is fixed client by client.
Moving clients early
Some acquirers move acquired clients onto their platform in waves before the merger weekend, which leaves less to convert that weekend.
The notice calendar
Plan back from the notice dates set by law.
The customer day one plan starts from the notices consumers are owed and the protections they keep. Your counsel sets the specifics; commercial clients' terms come from their agreements.
- 90 daysBranch closingsNotice to the regulator and to customers before a branch closes, and a notice posted in the branch.
- 30 daysAccount changesAdvance notice of changes to deposit account terms that could hurt the customer, under Regulation DD.
- 21 daysElectronic transfersAdvance notice of higher fees or liability, or fewer or tighter transfers, under Regulation E.
- Day oneThe switchOld routing numbers redirected for a period, old cards honored until activation, recurring bill payments set up again where they don't carry over.
- 6 monthsDeposit insuranceDeposits assumed in the merger stay separately insured for six months, longer for some time deposits.
The rules: Regulation DD, section 1030.5, Regulation E, section 1005.8 and deposit insurance, section 330.4. Not legal advice.
What catches acquirers out
Where merger integrations go wrong.
No utility
Some platforms can't deconvert.
One acquired platform had no deconversion utility at all, and the vendor confirmed none existed. Ask in the first month.
Mapping
Mapping goes through many revisions.
One merger's data mapping went through 35 revisions over more than four months. Plan for revision, and for the business and product SMEs who need to answer the questions.
One weekend
Roll the runbooks up into one.
A single platform's runbook alone can run upwards of 500 steps over 96 hours with some 50+ owners. Every platform, executing at once, competing for environments and resources. On a tight conversion window, the final mock confirms every migration code change landed, and the conversion weekend execution is feasible.
Logins
Day one problems show up at sign-in.
In one 2026 conversion, customers who enrolled early still couldn't sign in, and bill pay history didn't carry over. Credentials are the critical path.
Irreversible
An irreversible cutover with reduced testing.
A UK bank's acquisition-driven migration ran as one irreversible event, with testing quietly cut back. Regulators fined it nearly £49 million in 2022.
How Ignite supports you
How we support a merger integration.
We've supported merger conversion programs alongside acquirers and their other partners, in conversion project management, requirements, mapping and reconciliation.
01
Integration planning
Options, sequencing and the conversion plan, including moving clients before the merger weekend.
02
Conversion delivery
Technical project management, requirements, routing rules, mapping, mocks and the rolled-up runbook.
03
Reconciliation
Out of band, at every step, with business owners signing off on what they own.
04
Customer day one
Credentials, tokens, preview and the notice calendar, ready and rehearsed.
The market and its clock
Faster approvals leave less time to prepare.
180+
U.S. bank deals in 2025, worth about $49 billion, against 125 deals and $16.3 billion in 2024.
S&P data, via the Harvard Law School Forum, April 202694 days
median from announcement to close so far in 2026, down from 187 in 2024.
S&P data, via Global Finance, October 202685 days
the Federal Reserve's average processing time for merger applications in 2025, down from 101, with 145 approved.
Federal Reserve, June 202611%
of consumer deposits lost on average within three months of close in deals over $5 billion; over 17% for the bottom quarter. A vendor's benchmark.
Curinos, March 2026Over half
of the synergies in many banking deals come from technology, which is why the integration plan carries the deal's value. An advisory firm's view.
Deloitte, Banking M&A integrationMay 2025
The OCC restored expedited review and the streamlined application, and rescinded its 2024 merger policy statement. The FDIC withdrew its own.
OCC, May 2025Spend 30 minutes with us
Talk with us about your merger integration.
No pitch, no obligation. And if we're not the right team for it, we'll tell you that too.