How to build an M&A longlist

Building an M&A longlist lays the foundation for the entire M&A process. It covers all the potential target companies or buyers that could be considered for a project. But how do you turn this broad list into a focused, actionable shortlist? In this article, we show you how to use modern AI tools to build a high-quality longlist systematically, filter it by the most important criteria and arrive at the ideal basis for your decisions.

We compare longlists and shortlists side by side and give you concrete figures and best practices. You will also learn how ProxDeal lets you automate the entire process, saving you considerable time and resources.

What makes a good M&A longlist?

Criteria for a strong longlist

A good M&A longlist should be more than a mere collection of company names. It needs to be well structured, up to date and complete. Two criteria are decisive: it must be broad enough to cover all relevant options, and it must be of high enough quality to provide a sound basis for the M&A shortlist that is later derived from it.

Completeness of data

An M&A longlist should include as many of the relevant market participants as possible. In the M&A process, this means covering all potential buyers or target companies, which can vary by industry and region. Any relevant candidate missing from the list is a missed opportunity.

Up-to-date data

The list’s potential stands or falls with the quality of its data. Outdated information leads to wrong conclusions and poor decisions. It is therefore essential to have up-to-date data sources at your disposal.

Clear filter criteria

It is important to define clear criteria right from the outset of building the list – criteria that remain visible throughout the entire M&A process. Examples include industry, revenue or region. The result is a longlist that is not too broad – one of the most important criteria of all.

A data-driven basis for decisions

An M&A longlist is the factual basis for the selection process. The more metrics you include, the easier it becomes to build the shortlist later on.

Practical tip: automated longlist building with AI

Building a longlist manually can be very time-consuming, particularly in the M&A process. ProxDeal searches millions of websites for you, including all key company and specialist registers, and generates a longlist complete with all the relevant metrics.

Another feature – and a real time-saver – is built in as well: simply copy and paste the link to your website, and all the relevant fields are filled in automatically for you within a few minutes.

From longlist to shortlist – the decisive step

Once the longlist has been built, the actual qualification of the candidates begins. The goal is a focused shortlist of the companies that best fit your strategy.

1. Define your criteria

Before you start filtering, decide which criteria really matter:

• Strategic fit, e.g. product portfolio, market presence, synergies
• Financial metrics, e.g. revenue
• Deal history
• Geographical proximity or international expansion

2. Filter candidates automatically

Instead of assessing every candidate manually, you can use modern tools such as ProxDeal. It applies your filter criteria automatically to the entire longlist and prioritises the best matches. This saves time and ensures that the relevant candidates appear right at the top.

3. Prioritise candidates

The candidates that best match the defined criteria form the shortlist. This list then serves as the basis for your outreach decisions.

Longlist vs. shortlist at a glance

ProxDeal in practice – build longlists in minutes

Practical example – longlist and shortlist

ProxDeal significantly accelerates the entire process, from building the longlist to arriving at the shortlist.

Once generated, the list can be filtered and prioritised in just a few clicks – for example by strategic fit or revenue size.

This illustration clearly shows how the longlist is turned into a focused, decision-ready shortlist.

Benefits at a glance:

• Time savings: A longlist in just a few minutes instead of lengthy research
• Up-to-date data: Live analysis instead of outdated databases
• Quality: Structured tables with all the relevant metrics
• Seamless process: From longlist to shortlist, exportable for team workflows

This allows M&A advisors to concentrate on the strategic assessment instead of devoting their attention to gathering basic data.

Book a free demo now and experience all the benefits for yourself.