Most investors want to meet the founder who raised fifty million dollars before shipping a product. Mainsail Partners wants the other one - the founder who raised nothing, got to ten million in recurring revenue on customer cash and stubbornness, and now has a spreadsheet full of problems no amount of grit can solve alone. That founder is the entire business.
Founded in 2003 by Gavin Turner and Jason Payne, two alumni of the software-investing firm Summit Partners, Mainsail is a growth equity firm with a narrow and unfashionable thesis: back bootstrapped, founder-led business-to-business software companies, and help them scale without asking the founders to give up control or the culture they built. Over 22 years the firm has raised nearly $4 billion in committed capital and partnered with more than 100 companies. It keeps offices in San Francisco and Austin, Texas.
01 / THE THESISWhat Mainsail actually does
Mainsail invests roughly $30 million to $60 million at a time into software companies with $4 million or more in recurring revenue. It takes both minority and majority positions, and it concentrates its portfolio deliberately - fewer companies, more attention each. The firm targets four corners of the software market: vertical SaaS, financial technology, healthcare IT, and infrastructure or security software, with select horizontal SaaS mixed in.
The common thread is not a sector but a story. The companies Mainsail backs almost never raised outside money. They grew because customers paid them, which means they were profitable, disciplined, and - by the time they picked up the phone - stuck. Bootstrapping proves a business works. It also builds a ceiling: you cannot self-fund a national sales team, a second product line, and a data platform all at once out of monthly cash flow.
The best software companies aren't the ones raising headlines. They're ERP for metal-finishing shops and compliance software for fire inspectors.
02 / THE PORTFOLIOGloriously unglamorous software
Scroll Mainsail's portfolio and you find the plumbing of the real economy. There is Steelhead Technologies, ERP built for metal-finishing and fabrication shops. There is ProShop, management software for racquet and paddle clubs. There is Inspect Point, which handles fire and life-safety compliance, and JobNimbus and SmartMoving, which run contractors and moving companies. None of these will trend on tech Twitter. All of them are the kind of quietly essential tools their customers cannot switch off.
This is by design. Vertical software companies tend to have high retention, deep customer relationships, and pricing power - the exact ingredients that make a bootstrapped business durable and a growth-equity investment attractive. Mainsail is not hunting for the next consumer breakout. It is compounding boring, profitable software.
03 / THE DIFFERENCEAn operating team, not a board seat
Plenty of firms promise to "add value." Mainsail's version is unusually literal. It runs a 26-person, portfolio-facing team stocked with former Heads of Product, Pricing and Sales, VPs of Marketing and Customer Experience, CTOs, a CFO, and legal professionals. When Mainsail invests, the founder does not get a quarterly lecture. They get people who have already built the thing the company is trying to build - and who plug in to recruit executives, sharpen pricing, scale go-to-market, and stand up the data infrastructure a growing company suddenly needs.
Where the operations team plugs in
Since closing its previous fund in 2022, Mainsail has added more than 20 professionals, many of them senior operators with experience in AI, customer experience, demand generation, pricing, product, and revenue operations. In 2024 it launched Mainsail AI Labs, an internal program to help portfolio companies build AI-first products and teams rather than experiment blind. It also runs a talent-development program, LEAP, for leaders across its companies.
Our commitment to Texas has been there for a long time. This new office will put us front and center with this community.Gavin Turner, Co-Founder & Managing Partner
04 / THE BUSINESS MODELHow the firm makes money
Mainsail is structured like a classic growth equity manager. It raises capital from limited partners into flagship funds, then deploys it into a concentrated set of companies it holds for years, aiming to grow revenue and enterprise value before an eventual sale or recapitalization. The differentiator is what happens between the check and the exit: the operations team is the product as much as the money is.
In May 2025 the firm closed its seventh fund, Mainsail Partners VII, at its hard cap of $1.535 billion - the largest in the firm's history. It was oversubscribed and raised in under 100 days, faster than many startups close a single round. That fund pushed the firm's total committed capital to nearly $4 billion.
Fund VII, in context
05 / THE CUSTOMERWho actually picks up the phone
Mainsail's customers are founders and management teams of bootstrapped B2B software companies in the United States and Canada, usually somewhere between $5 million and $50 million-plus in recurring revenue. These are people who have proven they can build and sell, and who now face the harder second act - turning a good company into a market leader. For them, the appeal is specific: capital to invest behind growth, and a bench of operators to lean on, without surrendering the culture that got them here.
06 / THE MARKETWhere Mainsail fits
The firm sits in growth equity - the stage between venture capital, which funds companies before they have proven economics, and buyout private equity, which typically takes full control of mature businesses. Its neighbors on the software side include Summit Partners, TA Associates, JMI Equity, Spectrum Equity, and Susquehanna Growth Equity. What separates Mainsail is the deliberate focus on the never-raised founder and the size of the operating team behind each deal.
The bet is aging well. As venture capital has cooled on unprofitable growth, capital-efficient, bootstrapped software has become one of the more coveted categories in private markets - which helps explain how Fund VII filled up in three months. The founders Mainsail spent two decades courting are, suddenly, the ones everyone wants.
Bootstrapping proves a business works. It also builds a ceiling. Closing that gap is the whole job.
07 / THE ORIGINA Summit playbook, reborn
Turner and Payne left Summit Partners with a memory of what worked in the 1990s: finding profitable, fast-growing software companies that had bootstrapped their way up and simply needed liquidity and a partner. They rebuilt that idea for the SaaS era, added an operations team it did not originally have, and grew from a small shop into a firm managing billions. In 2021 they opened the Austin office to sit closer to Texas's founder-led software scene, adding to the San Francisco base.
The name is the tell. A mainsail is the primary sail on a boat - the one that catches the wind and drives the vessel forward, while the captain steers. It is a fitting metaphor for a firm that wants to be the wind, not the wheel.