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The M&A Transaction Lexicon
Lexicon (noun): the total vocabulary of a language, a specific subject, or a person's mental word knowledge.
Common Vocabulary Across the Transaction Lifecycle
Version 2.2 (preview) · Terminology and regulatory references current as of September 2026 · Stephen Getty | stephengetty.com
A semantic model of the transaction
This lexicon is organized around one idea: a transaction is a single event seen from at least two sides. The buyer's integration and the seller's separation are mirror images, and much of the vocabulary is shared. An integration management office and a separation management office play the same role; Day 1, transition services, and standalone readiness arise on both sides; RemainCo and SpinCo are the two halves of one separation. The lifecycle hierarchy of program, phase, stage, sub-stage, activity group, activity, and task, the milestone roadmap, and the operating-model layers form a common frame within which every workstream can locate its own terms.
How to use this lexicon
Entries are grouped into a general grounding section, holding the terms every stakeholder should know, followed by workstream sections. Within each section entries are alphabetical. Cross-references shown as "See also" are clickable. The alphabetical index links every term to its definition, and the search box filters entries live. Written for broad usage with US conventions as the default. Applicability tags such as [United Kingdom] or [Multiple jurisdictions] mark terms whose relevance depends on where, or how, a deal is structured; an untagged term is treated as general.
Structure of a transaction program
| Level | Definition | Example |
|---|
| Program | The entire integration or separation effort | Acquisition or divestiture of a business |
| Phase | A major time segment bounded by milestones or gates | Day 1 Readiness and Execution |
| Stage | A subdivision of a phase | Discovery, Design, Implement |
| Sub-stage | A refined focus on a specific division of work | Design collaboration solutions |
| Activity group | An aggregated set of activities modularizing similar work | Design the Day 1 migration wave approach |
| Activity | A body of related work within a phase and workstream | Design the Day 1 migration for one wave |
| Task | The lowest practical unit of planned work, with an owner | Configure federation for site directory |
| Workstream | A functional lane running across all phases | IT, Finance, HR, Legal |
| Milestone | A fixed-point event in time | Close / Day 1 |
| Gate | A decision checkpoint between stages or phases | Day 1 Readiness gate |
The lifecycle milestones
| Milestone | Definition |
|---|
| Letter of intent | Preliminary terms agreed; diligence access opens |
| Signing | Definitive agreement executed; ownership not yet transferred |
| Signing to close (phase) | The window for regulatory clearance and program planning |
| Close (completion) | Legal transfer of control; the transaction becomes effective |
| Day 1 | First operating day under new ownership; the principal continuity milestone |
| Day 100 (phase) | Conventional early horizon to assess stabilization and progress |
| TSA exit (separations) | Standalone capability reached, by service and asset |
| End state (target state) | Target operating model live; program teams disband |
The acronym and abbreviation reference (General, Regional, and Jurisdiction-specific tables) sits here in the master and pours into the published page at go-live.
Part I. General grounding
The shared vocabulary every stakeholder needs: the lifecycle, the program hierarchy, the governance scaffold, the operating model, and concepts that span integration and separation.
Activity. A defined body of related work within a phase and workstream, sitting below an activity group and above individual tasks. Activities group tasks toward a deliverable. Activity group. An aggregated set of related activities, used to modularize similar work into tranches or waves. Sits below a sub-stage and above individual activities. Announcement. Public disclosure that a transaction has been agreed or is proposed. Business as usual (BAU). The steady, ongoing operation of the business, as distinct from the transaction program. Handover to BAU is a common definition of a program's end. Business capability. What an organization must be able to do to execute its strategy, independently of how it is organized. Capabilities anchor operating-model design because they change more slowly than structure. Business continuity. The overriding Day 1 objective that the affected organizations keep operating without interruption through the transition. Business model. How an organization creates and captures value, as distinct from its operating model, which is how it runs. Close (completion). The legal point at which the transaction becomes effective and control transfers, subject to the transaction documents. Critical path. The sequence of dependent activities that determines the shortest possible timeline for the program or a target objective. Slippage on the critical path slips the whole program. Current operating model (CMO). The organization's operating model as it exists before the transaction, and the baseline against which the target is designed. Cutover. The coordinated switch of a system, service, or process from one operational state to another at a defined point.See also: Coexistence; Rollback; Hypercare.
Day 1. The first operating day under the post-transaction ownership or structure. It usually coincides with, or immediately follows, Close, and is the principal business-continuity milestone. It does not imply that integration is complete or that a separated entity is operationally independent. Day 1 readiness. The state of preparation to operate safely and credibly from the moment of Close, covering continuity, access and security, communications, and legal guardrails. Distinct from integration being complete.See also:
Day 1;
Readiness checkpoint.
Day 100. A conventional early horizon (a phase, not a single point) used to assess stabilization, initial synergy capture, and progress toward business-as-usual ownership. The actual horizon varies and may be expressed as Day 60, Day 90, or Day 100. Deal rationale (deal thesis). The strategic and economic reasoning for the transaction, from which objectives and synergy targets are derived. Degree of integration. How far the two organizations will be combined, ranging from full integration through partial or light-touch to standalone. Deliverable. A defined output produced by an activity or workstream, subject to review at a gate. Dependency. A relationship in which one activity or task cannot start or finish until another does. Discovery. The post-signing current-state assessment that informs integration or separation design and builds on due-diligence findings. End state (steady state, target state). The defined finish line at which program teams disband, the program closes, and the target operating model is live. An undefined end state is a common cause of stalled programs. Future Mode of Operation (FMO). The target-state operating model, paired with the Current Mode of Operation. Gate (stage gate). A decision checkpoint between stages or phases at which deliverables are reviewed against defined criteria and the program is authorized to proceed, or not. Governance. The structure of decision rights, forums, cadence, and controls through which the program is directed, and one layer of the operating model. Integration. The bringing together of an acquired or merged business with the acquirer, across people, processes, technology, and data, to realize the deal rationale. The buy-side counterpart of separation. Integration blueprint. The early planning document that aligns workstreams and their deliverables to the target end state. Integration lead. The person who runs the program day to day, reporting to the steering committee. Integration Management Office (IMO). The central body that plans, coordinates, and governs all workstreams and translates the deal rationale into delivery. Its separation counterpart is the SMO. Integration thesis. The specific statement of how a given transaction will create value and how far the businesses will be combined. Interim operating model. A temporary operating arrangement in force between Day 1 and the target end state, frequently underpinned by transition services. Legal Day 1 (LD1). Firm-specific usage, generally synonymous with Close. This lexicon prefers Day 1 for the operational milestone and Close for the legal event. Milestone. A fixed-point event in the transaction or program, such as Signing, Close, or Day 100. A milestone marks time; it is not a span of work. Operating model. How an organization runs, expressed through its business capabilities, organization structure, processes, technology, data, and governance. Operational Day 1 (OD1). Firm-specific usage, most often the seller's view of when a separated entity operates independently. Not a universal milestone; treated here as perspective-dependent. Phase. A major time segment of the lifecycle, bounded by milestones or gates. Phases apply across all workstreams and need not follow a strict waterfall. Program. The whole integration or separation effort, comprising all workstreams, phases, and governance. RemainCo (ParentCo). The business and entity that remains with the parent after a separation, as distinct from the separated business.See also:
SpinCo;
Divestiture;
Stranded cost.
Separation. The disentangling of a business from its parent so that it can transfer to a buyer or operate independently, including the allocation and transition of people, assets, contracts, processes, data, systems, and services. The sell-side mirror image of integration. Separation Management Office (SMO). The divestiture counterpart of the IMO, coordinating a carve-out or separation. Signing. Execution of the definitive agreement. Ownership does not normally transfer at signing. Signing to close. The window (a phase) between signing and close, used for regulatory clearance and program planning, in which Day 1 and the longer horizon are orchestrated. SpinCo (NewCo, CarveCo). The business and entity being separated from the parent. The counterpart to RemainCo.See also:
RemainCo;
Spin-off;
Carve-out.
Stabilization. The period following Day 1 in which operations are steadied, gaps closed, ownership confirmed, and the recurring governance cadence established. Stage (sub-phase). A subdivision of a phase, used to sequence work and to position gate reviews. On complex transactions a stage may be broken into sub-stages. Stakeholder. Any party with a material interest in the transaction or its execution, from the board to regulators to affected employees. Steering committee (SteerCo). The executive decision forum above the IMO or SMO, chaired by the sponsors, that sets objectives, resolves escalations, and authorizes progression at gates. Sub-stage. A subdivision of a stage that narrows the focus to a specific division of work within it, used on larger or more complex transactions where a stage is too broad to plan as one unit. Target Operating Model (TOM). The future-state design of how the combined or separated organization will run to deliver its strategy. Expressed through six layers: business capabilities, organization structure, processes, technology, data, and governance. Task. The lowest practical unit of planned work, normally assigned to a specific owner and contributing to an activity or activity group. Transition Services Agreement (TSA). An agreement under which one party provides temporary services, or continued use of assets, to the other after close, with defined scope, service levels, pricing, and an exit plan per service.See also: Reverse TSA; TSA exit; TSA service schedule.
Workstream. A functional lane of work running across all phases, led by a workstream lead. Large workstreams may be broken into smaller ones.See also:
Phase;
Workstream charter.
Part III. Legal and regulatory
Full content for this section pours in from the master. These are representative entries showing region tags and cross-links.
Committee on Foreign Investment in the United States (CFIUS). [United States]The US interagency body that reviews foreign investments for national-security risk and can condition, or block, a transaction.See also: Foreign investment review; Conditions precedent.
Foreign Investment Review Board (FIRB). [Australia]The Australian non-statutory body that examines foreign investment proposals and advises the Treasurer, who holds the decision.See also: Foreign investment review; Conditions precedent.
Data protection (GDPR, UK GDPR). [European Union; United Kingdom]The EU General Data Protection Regulation (Regulation (EU) 2016/679) and its UK counterpart govern the handling of personal data, bearing on diligence data sharing, cross-border transfer, and the migration or separation of employee and customer data.See also: Due diligence; Disentanglement; Clean team.
Part IV. Finance and value
Full content for this section pours in from the master. These are representative entries showing region tags and cross-links.
EBITDA. Earnings before interest, taxes, depreciation, and amortization, a common proxy for operating cash generation used in valuation and as the base for the enterprise-value multiple. Quality of earnings (QoE). A financial due-diligence analysis testing how sustainable and accurate a target's reported earnings are, adjusting for one-offs and accounting choices.See also:
Due diligence;
EBITDA.
Part VII. People and change (HR and OCM)
Full content for this section pours in from the master. These are representative entries showing region tags and cross-links.
TUPE. [Great Britain]The Transfer of Undertakings (Protection of Employment) Regulations, derived from the EU Acquired Rights Directive. In a qualifying transfer, assigned employees generally transfer automatically to the new employer on their existing terms.See also: Acquired Rights Directive; Works council; Collective consultation.
WARN. [United States]The Worker Adjustment and Retraining Notification Act, requiring advance notice of certain plant closings and mass layoffs. The US-side counterpart to consultation obligations elsewhere.See also:
TUPE;
Collective consultation;
Rebadging.
Part II. Corporate development and deal shaping
Content pours in from the master when final.
Part V. Tax and structuring
Content pours in from the master when final.
Part VI. Program governance and PMO
Content pours in from the master when final.
Part IX. Commercial and go-to-market
Content pours in from the master when final.
Part X. Operations and separation execution
Content pours in from the master when final.
Alphabetical index
Every included term, linked to its entry. In the full build this covers all sections.