How to Find Add-On Acquisition Targets for Your Portfolio Companies

Add-on acquisitions are often where PE value creation happens. A platform company in a fragmented market, a well-timed bolt-on that expands geography or product — the math works when you can find the right targets at the right time. The challenge is that finding those targets systematically is harder than it sounds.

Why add-on sourcing is different from platform sourcing

When you're sourcing platform investments, you're casting a wide net — scanning a broad market for companies that fit a thesis. Add-on sourcing is different. You're starting with a known company and looking for specific types of adjacencies: similar products in new geographies, complementary capabilities, customer base overlaps, competitors in adjacent verticals.

The criteria are more specific and more contextual. "Find me companies like our portfolio company in the Midwest with under 100 employees that serve the same customer type but through a different distribution channel" is not something a keyword search handles well. The filter set becomes unwieldy and still misses the targets that describe themselves in different language.

The traditional approach and its limits

Most PE firms approach add-on sourcing through a combination of:

• Asking the portfolio company's management team who they know
• Searching industry databases for companies in the same SIC/NAICS code
• Hiring intermediaries to run a targeted process
• Monitoring trade publications and industry events

These approaches work but they're slow, expensive, and incomplete. Management teams know their direct competitors but often miss companies in adjacent niches. NAICS codes are too blunt an instrument for nuanced thesis matching. Intermediaries bring you companies that are already in a process.

The best add-on targets are often companies that aren't actively looking to sell, aren't in any intermediary's pipeline, and wouldn't show up in a keyword search because they describe their business differently than the portfolio company does.

A more systematic approach

The most effective add-on sourcing starts with the portfolio company itself as a search anchor, then expands outward in several directions:

Similar product, different geography — Companies doing essentially the same thing as the portfolio company in markets it doesn't serve. These are natural acquisition targets for geographic expansion.

Adjacent product, same customer — Companies selling to the same buyer persona with a complementary product. These targets create cross-sell opportunities and often command lower multiples because they're smaller or earlier stage.

Direct competitors — The obvious ones, but also the ones that are smaller and less well-known. In fragmented markets there are often dozens of regional players that never make it onto a traditional competitor list.

Technology or capability adjacencies — Companies whose technology would extend the portfolio company's product without requiring organic development time.

How vector similarity search changes this

The most efficient way to map these categories is vector similarity search — the same technology used in modern AI tools. Instead of searching for companies that match a set of keywords or filter criteria, you use the portfolio company itself as the search query.

Radar does this directly. Point it at a platform company and it generates a vector from that company's description, specialties, and market positioning, then searches across millions of private companies for the closest matches by cosine similarity. You can layer filters on top — geography, employee count, funding stage — to narrow to specific adjacency types.

The results surface companies that are similar in meaning, not just in terminology. A portfolio company that describes itself as "predictive maintenance software for manufacturing" will surface lookalikes that use language like "condition monitoring for industrial equipment" or "equipment health analytics for factory floors" — companies that a keyword search would miss entirely.

Building a systematic add-on pipeline

Rather than running add-on searches as one-off exercises, the firms that do this well treat it as a continuous process:

Start at the beginning of the hold period. The best time to identify add-on targets is right after the platform acquisition closes, not two years later. Build the target map early so you have time to develop relationships before you need them.

Segment by priority. Not all adjacencies are equal. Rank targets by strategic fit, accessibility, and estimated timing. The ones that are most similar to the platform and most likely to be receptive to a conversation should get attention first.

Monitor for signals. Companies that are approaching a natural transition point — leadership change, new institutional investor, revenue plateau — are more likely to be receptive to a conversation. Monitoring for these signals means you can time outreach appropriately rather than reaching out cold at a random point in the company's lifecycle.

Update the map regularly. Markets change. New companies emerge, existing ones get acquired, others pivot. A target map built at acquisition will be stale within 18 months without ongoing updates.

The timing advantage

In fragmented markets, the difference between a good add-on and a missed opportunity is often just timing. The firm that identifies a target six months before it goes to market, builds a relationship, and is ready to move quickly has a structural advantage over the firm that sees it in a process two years later with four other bidders.

Systematic, continuous add-on sourcing is how you get there first.

Radar has a similar company search built specifically for this workflow. Try it on one of your portfolio companies and see what the target landscape actually looks like, or book a demo to see it with your own deal flow.