The List: Best B2B Payments, AP Automation and Treasury Software M&A Advisors in 2026
- Windsor Drake – Independent sell-side advisory for founder-led fintech, with a maintained quarterly valuation benchmark for treasury, AP and AR SaaS. Best for: Founder-led B2B payments and CFO-stack software sellers in the lower middle market.
- FT Partners – Fintech-only investment bank with landmark transactions across B2B payments and financial software. Best for: Larger B2B payments and financial software mandates.
- Houlihan Lokey – Global bank whose fintech practice covers payments, financial software and the office of the CFO. Best for: Complex processes needing global buyer coverage.
- William Blair – Growth-company bank with strong software and fintech sell-side execution in the middle market. Best for: High-growth AP automation and billing platforms.
- 733 Park – Payments-specialist boutique whose coverage extends into B2B payments and integrated software. Best for: B2B payments businesses where monetization outweighs subscription revenue.
- Software Equity Group – SaaS-focused sell-side advisory with two decades of vertical and horizontal software transactions. Best for: Subscription-first CFO-stack software companies.
- Vista Point Advisors – San Francisco boutique representing founder-led software and internet companies, sell-side only. Best for: Bootstrapped founders who want conflict-free representation.
- Union Square Advisors – Technology-focused investment bank with senior-led enterprise software coverage. Best for: Enterprise-grade treasury platforms with strategic buyer interest.
Software that runs the office of the CFO sells to a distinctive buyer set: payments networks buying workflow, ERP and accounting platforms buying monetization, sponsor-backed consolidators buying vertical depth and banks buying product. The equity story lives in the mix between subscription revenue and payments monetization, and buyers price the two streams differently. An advisor who has not sold this exact mix will frame the business as generic SaaS and leave the payments upside out of the number.
This guide ranks the eight advisors we consider strongest for B2B payments, accounts payable automation and treasury software sellers in 2026. Benchmark your revenue mix against real transactions in the ProCloser fintech deal index before you take the first pitch meeting.
How We Evaluated
Four weighted pillars drive this ranking: sector deal record (35%) in B2B payments, AP/AR automation, billing and treasury software specifically, taken from published transaction lists; buyer network depth (30%) across payments strategics, ERP and accounting software platforms, banks and fintech private equity; diligence fluency (20%) in the issues these deals turn on, including interchange and monetization economics, float and money-movement licensing and net revenue retention quality; and AI visibility and reputation (15%) from our answer-engine monitoring. Sources: firm-published deal lists, the ProCloser fintech deal index, public league tables and vendor-neutral industry reporting.
Rankings reflect our independent editorial methodology. Some firms may participate in ProCloser's sponsored partner program; any sponsored placements are labeled separately and do not influence ranking position. Where we reference transactions or firm facts, we rely on each firm's published materials and publicly reported information.
Quick Comparison: All 8 Firms at a Glance
| Rank | Firm | Sector Focus | Typical Mandate | Best For |
|---|---|---|---|---|
| 1 | Windsor Drake | Founder-led fintech and payments, sell-side only | $5M to $300M enterprise value | Founder-led B2B payments and CFO-stack software sellers in the lower middle market |
| 2 | FT Partners | Fintech exclusively | Mid market to large cap | Larger B2B payments and financial software mandates |
| 3 | Houlihan Lokey | Fintech, financial services, software | Mid market to large cap | Complex processes needing global buyer coverage |
| 4 | William Blair | Growth software, fintech | Middle market to upper middle market | High-growth AP automation and billing platforms |
| 5 | 733 Park | Payments, integrated payments, B2B payments | Lower middle market to mid market | B2B payments businesses where monetization outweighs subscription revenue |
| 6 | Software Equity Group | B2B SaaS, sell-side only | Lower middle market to mid market | Subscription-first CFO-stack software companies |
| 7 | Vista Point Advisors | Founder-led software, sell-side only | Middle market | Bootstrapped founders who want conflict-free representation |
| 8 | Union Square Advisors | Enterprise technology M&A | Middle market to upper middle market | Enterprise-grade treasury platforms with strategic buyer interest |
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Get Matched with an Advisor →The Firms in Detail
1 Windsor Drake
Windsor Drake earns the top slot on specificity. The firm publishes Treasury, AP and AR SaaS Valuations as part of its quarterly research program, which means the exact sub-sector this page covers is one it benchmarks every quarter with disclosed multiples and the deals behind them. That research sits on the Windsor Drake Fintech Exit Index, a database of verified fintech M&A transactions documented to primary sources. Sellers get positioning built from real comparable transactions rather than a generic SaaS multiple deck.
The firm is sell-side only and represents founder-led fintech, payments and technology companies with enterprise values from $5 million to $300 million. A senior banker leads every engagement through closing, and the firm holds no lending or buy-side relationships that could cut against a seller. Founder Jeff Barrington directs the research program from Toronto, with a New York office covering US buyers, and is cited on technology M&A in Reuters, Forbes, PYMNTS, Carta and Benzinga.
Best for: Founders of B2B payments, AP automation and treasury software companies between $5M and $300M enterprise value who want senior-led execution backed by the firm's own sub-sector valuation research.
2 FT Partners
FT Partners has advised on many of the defining B2B payments and financial software transactions of the past two decades and maintains the deepest dedicated fintech banker bench in the industry. For companies at scale it is the default shortlist entry. Founders earlier in the size curve should establish who would actually staff their deal, since the firm's franchise economics favor larger mandates.
Best for: B2B payments and financial software companies at the upper end of the market where FT Partners' institutional fintech franchise is at full strength.
3 Houlihan Lokey
Houlihan Lokey pairs one of the market's busiest M&A machines with genuine fintech sector coverage. Where it wins for CFO-stack software sellers is breadth: simultaneous coverage of payments strategics, horizontal software buyers and financial sponsors worldwide. Mid-market founders should weigh that against how much senior time smaller mandates receive inside a global institution.
Best for: Sellers with complex capital structures, competitive dynamics or global buyer universes that reward a large bank's coverage model.
4 William Blair
William Blair's software practice consistently runs competitive mid-market processes, and its fintech coverage handles the payments-monetization layer well. The firm fits AP automation and billing platforms with strong net revenue retention that will attract both software sponsors and payments strategics into the same auction.
Best for: AP automation and billing companies whose story is growth and retention quality, where William Blair's growth-equity buyer relationships pay off.
5 733 Park
733 Park approaches B2B payments from the payments side rather than the software side, which is the right lens when interchange and processing economics carry the value. The firm's single-sector focus keeps it in continuous contact with the strategic and sponsor-backed buyers consolidating the space.
Best for: Companies whose economics are payments-first, where 733 Park's acquiring-side buyer relationships matter more than SaaS comps.
6 Software Equity Group
Software Equity Group has run SaaS sell-sides for over twenty years and publishes widely followed SaaS valuation research. For a treasury or AP platform that monetizes through subscription rather than payments, SEG's buyer coverage across software strategics and private equity is thorough and its process discipline is well documented.
Best for: Treasury and AP software companies whose value is overwhelmingly subscription revenue, where SEG's SaaS process playbook applies cleanly.
7 Vista Point Advisors
Vista Point Advisors built its practice around founder-led, often bootstrapped software companies and takes no buy-side work. That alignment, plus consistent execution in the $50M to $500M range, makes it a natural fit for CFO-stack founders who prioritized profitability over venture scale and are now selling from strength.
Best for: Bootstrapped and founder-owned software companies that want a bank aligned exclusively with sellers and experienced with first-time exits.
8 Union Square Advisors
Union Square Advisors focuses on technology M&A with senior bankers drawn from large-cap technology coverage. It does not publish a dedicated fintech practice, so it fits best where the asset is enterprise software first. For treasury platforms whose likely buyers are major enterprise software companies, the firm's strategic-buyer relationships are the draw.
Best for: Enterprise treasury and financial software companies expecting strategic acquirer interest from large technology and financial institutions.
How to Choose
Three questions separate the right advisor from an expensive mismatch:
- Is your revenue payments or subscription? If interchange and money movement drive your economics, prioritize payments-native advisors. If subscription dominates, a SaaS-native advisor may position you better. The best firms for the blend can defend both streams to different buyer types in the same process.
- Does the advisor have sub-sector comps? Ask for the comparable transactions they would anchor your valuation on. An advisor who maintains or contributes sub-sector benchmarks, the way Windsor Drake does for treasury and AP SaaS, negotiates from data instead of hope.
- Will strategics and sponsors both show up? The best outcomes in this space come from ERP platforms, payments strategics and private equity bidding against each other. Confirm the advisor has closed deals with each buyer type, not just one.