Mapping M&A Relationship Networks

• PE firms source from a range of Investment Banks. Among PE firms with 15 or more bank-advised deals, the median PE firm sourced only 14% of its deals with a single bank.
• PE - Law firms relationships are more consistent. The median PE firm uses the same law firm on 38% of acquisitions.
• Legal work is more concentrated. Kirkland & Ellis alone appears on 12% of law-advised deals. No bank comes close: Houlihan Lokey, the busiest, appears on 4% of bank-advised deals.
• Most relationships are one-offs, especially with banks. 8,880 of 10,588 PE and bank pairs (84%) worked together on only one deal. For law firms it is 4,886 of 6,683 pairs (73%), so PE firms are more likely to return to the same law firm.

10 large PE firms & their related Investment Banks

The 10 most acquisitive PE firms get 68% of their bank-advised deals from banks outside the top 10. Inbound deals to PE firms is spread wide, with no single bank holding a large share.

PE firms on the left, banks on the right. Band width = number of shared deals. Grey bands go to banks outside the top 10.

10 large PE firms & their related Law Firms

Legal work runs in tight, repeat relationships. Only 38% of these firms' law-advised deals go outside the top 10 law firms, against 68% for banks, and the bands are far thicker.

PE firms on the left, law firms on the right. Band width = number of shared deals. Grey bands go to law firms outside the top 10. Winston Taylor, the 10th busiest law firm, has no deals with these PE firms, so 9 are shown.

• Insight Partners and Willkie Farr & Gallagher are close to exclusive. They share ~93% of deals.
• Several firms have a clear house counsel. Thoma Bravo prefers Kirkland & Ellis, TA Associates uses Goodwin Procter, and H.I.G. Capital frequently uses McDermott Will & Schulte.
• The largest sponsors split between two firms. KKR & Co. and Blackstone Group each divide their work mainly between Simpson Thacher & Bartlett and Kirkland & Ellis.
• Not everyone fits the pattern. Foresight Group's 75 law-advised deals go almost entirely to smaller firms outside the top 10.

One firm at a time

Putting a PE single firm at the center of their deal relationship network shows the two patterns most clearly: a PE firm with many light bank ties, and a law firm with many deep PE ties.

KKR & Co. and its top 15 banks. The number in each circle is shared deals.

Kirkland & Ellis and its top 15 PE clients. The number in each circle is shared deals.

Kirkland & Ellis - each of its top 15 clients brought 17 or more deals, led by Thoma Bravo, Vista Equity Partners and Gryphon Investors. These established relationships provide repeat business to the law firms as the preferred advisor for M&A transaction work.

The whole network

Across every firm, the bank network is a wide web of small ties, while the law network forms a few large clusters around a handful of law firms.

All 10,588 PE and bank pairs. Navy = PE firm, orange = investment bank. Larger circle = more deals.

All 6,683 PE and law firm pairs. Navy = PE firm, blue = law firm.

The full views are dense, so below we show a slice of the data that represents only the repeat relationships.

The 32 PE and bank pairs with 7 or more shared deals.

PE - IB deal relationships form small groups, with Goldman Sachs and William Blair & Company as the busiest meeting points.

The 64 PE and law firm pairs with 13 or more shared deals.

PE - Law Firm deal relationships - Kirkland & Ellis sits at the center of one large cluster, with Latham & Watkins, Ropes & Gray and Simpson Thacher & Bartlett forming smaller hubs nearby.

What it means

• For bankers: PE firms acquire portfolio companies from a broad range of investment banks. Deal quality beats prior deal relationships. Private Equity Info (now TruSight Intelligence) helps investment bankers find the best, highly targeted PE buyers for their deals.
• For PE firms: there's a long, largely untapped tail to the distribution of investment banks in the marketplace.
• For law firms: the market is more concentrated. Kirkland & Ellis appears on ~12% of law-advised PE acquisitions.

Notes on the data

• More deals now list an advisor. About 15% of PE deals had a bank listed in 2016. That rose to 33% in 2025 and 42% so far in 2026. Law firms follow the same curve, from 13% to 31% and 37%.
• Limits. Deal counts are numbers of deals, not deal value, and larger firms naturally show higher counts. Only deals with an advisor listed are included, so real relationships may be stronger than shown.