Day 1 readiness: what has to work the morning the deal closes

What Day 1 means

Day 1 is the first day the business operates under new ownership, usually the day the transaction closes. Legally, the buyer now owns the shares or assets. Practically, everything that depended on the seller, or on people who are now uncertain about their future, has to keep working.

The test of a good Day 1 is that customers notice nothing they were not told about, employees know who they work for and that they will be paid, and no system, account or payment flow is left in an unknown state. Ambitious changes (new systems, new structures, rebranding) belong to the 100-day plan, not to Day 1.

Must-have versus nice-to-have

Most Day 1 plans fail by trying to do too much. A simple rule: an item is a Day 1 requirement if, without it, the business would breach a law, miss a payroll, lose a customer, or expose data or money. Everything else goes on the 100-day list. Agree that split with the deal team and the target's management before closing, and hold to it.

Before closing: what can and cannot be prepared

Until the deal closes, the buyer does not control the target. Antitrust rules limit how far a buyer can direct the target's business before closing, and competitively sensitive information is usually exchanged through clean teams under counsel's guidance. Day 1 planning therefore works with what can lawfully be shared: process maps, system inventories, contract lists, organisation charts and named contacts. The plan is prepared jointly; execution waits for closing.

The Day 1 checklist by function

Leadership and governance

• Board and officer changes effective at closing; signing authorities updated.
• Bank mandates changed so the right people can authorise payments, and the wrong ones cannot.
• A decision-rights matrix for the first weeks: what local management decides, what goes to the new owner.

Communications

• Employee announcement on the morning of Day 1, followed by manager briefings with a short question-and-answer sheet.
• Customer and supplier letters that say what changes (if anything) and what does not.
• A clear statement that bank details are not changing, or exactly how a change will be confirmed. Deals are a well-known pretext for fraudulent payment-redirection requests.
• Regulator and works-council notifications where required.

People and payroll

• The first payroll after closing confirmed with the payroll provider, including any change of employing entity.
• Benefits and pensions continuing without a gap.
• Key-person retention arrangements signed and communicated to the people concerned.

Finance

• Cash, treasury and intercompany flows working; any cash sweeps to the seller stopped.
• Closing balance sheet cut-off agreed, for the completion accounts or locked-box mechanism.
• Reporting calendar for the first month: what the new owner receives and when.

Legal and commercial

• Change-of-control consents obtained for contracts that require them, including software licences.
• Insurance in place from closing, including cyber cover.
• Permits and licences that depend on ownership confirmed or re-applied for.

IT and security on Day 1

Technology is where a careless handover does the most damage in the shortest time. The aim on Day 1 is control, not integration.

Identity and access

• A list of every administrator and privileged account (directory, cloud consoles, domain registrar, DNS, email, firewalls, finance systems, code repositories) and who holds them.
• Credentials for those accounts rotated on Day 1, especially where departing owners, the seller's IT staff or outside contractors held them.
• Multi-factor authentication confirmed on every privileged and remote-access account.
• Leaver process ready for anyone who exits at closing, with access removed the same day.

Email, domains and communications

• Domain names and DNS registered to the right legal entity, with renewal dates known.
• Email continuing to work; any change of addresses or branding deferred until it can be done properly.

Networks and connectivity

• No network interconnection between buyer and target on Day 1 unless the target's security posture has been assessed. Connecting first and assessing later imports whatever is already inside.
• If the business was carved out, the network services provided by the seller under a transition services agreement working from the first minute.

Systems, data and licences

• An owner named for every business-critical application, with a support contact that works on Day 1.
• Software licences that terminate or need consent on a change of control identified, and resolved or covered.
• Backups confirmed to exist, to be recent, and to restore. Ask for evidence of a test restore, not a policy.
• Security monitoring and incident response: who is on call, who decides, and who the cyber insurer's breach line is.

Day 1 in a carve-out

When the business is bought out of a larger group, it usually cannot run on its own on Day 1. The seller keeps providing services (IT, payroll, finance processing, sometimes facilities) under transition services agreements while the buyer builds or buys its own. In that case Day 1 readiness means every service the business needs is either standalone or covered by a TSA with a named contact and a service level. Our guide to carve-outs and separation covers how those agreements are scoped and exited.

Running Day 1

• Rehearse. Walk through the first 48 hours with the people who will execute it, function by function.
• Command centre. One place, physical or virtual, where issues are logged, owned and closed, for the first one or two weeks.
• Issue log. Every problem recorded with an owner and a time; reviewed twice a day at first.
• Hand over to the 100-day plan. Items that were deliberately deferred become workstreams with owners.

Where diligence feeds Day 1

Most Day 1 surprises were visible in the data room: the administrator accounts held by a founder, the licence that terminates on a change of control, the backup that has never been restored, the security tool that belongs to the seller's group. A technology diligence that lists these findings with their evidence gives the Day 1 team its checklist before signing.

Share deals and asset deals

What has to happen on Day 1 depends on how the deal is structured.

• Share deal: the buyer acquires the company itself. Contracts, employees, licences and accounts stay with the same legal entity, so continuity is mostly automatic. The risks are the contracts with change-of-control clauses and the services the company received from its former owner.
• Asset deal: the buyer acquires assets and contracts, which move to a new legal entity. Contracts have to be assigned or novated, often with the counterparty's consent; bank accounts, tax registrations, permits and software licences have to be set up for the new entity; and employment may transfer under local law (in the EU, rules implementing the Acquired Rights Directive; in the UK, TUPE). Asset deals need a much longer Day 1 list.

A Day 1 communications timeline

Payment fraud around closing

The weeks around a deal are a favourite moment for payment-redirection fraud: an email that appears to come from a supplier, the seller or the new owner, asking for payments to go to a new account. The controls are simple and should be in place before Day 1:

• Any change to supplier or customer bank details is confirmed by phone to a number already on file, never to one given in the request.
• Two people approve any payment above an agreed threshold during the transition.
• Customers are told in writing how a genuine change of bank details will be communicated.
• Email security (sender authentication for the company's domains) is checked before closing.

Who owns the Day 1 plan

A Day 1 plan needs one accountable lead, usually from the buyer's integration or operations team, and one counterpart in the target's management. Each function (finance, HR, IT, legal, commercial) has a named owner for its checklist. The deal team stays close but does not run it; their attention is on closing the transaction itself.

Common pitfalls

• Treating Day 1 as the start of integration rather than a continuity exercise.
• Discovering on Day 1 who holds the administrator passwords.
• Connecting networks before assessing the target's security.
• Announcing changes to bank details by email, which is exactly what fraudsters imitate.
• Forgetting the people who leave at closing still have access.