Who is Mainsail Partners?
Mainsail Partners is a growth equity firm founded in 2003 that invests only in bootstrapped, founder-led B2B software companies. The firm operates from offices in San Francisco and Austin, and co-founder Gavin Turner serves as Managing Partner. Mainsail Partners has invested in more than 100 software companies since 2003.
Mainsail invests from closed-end funds and manages nearly $4 billion in total commitments. Fund V closed at $531 million in February 2020, Fund VI closed at $915 million in April 2022, and Fund VII closed at $1.535 billion in April 2025 after fewer than 100 days of fundraising.
Fund structure shapes buyer behavior. A closed-end fund must return capital to its limited partners on a schedule, so Mainsail sells or recapitalizes portfolio companies rather than holding them permanently. In 2025 Mainsail exited Sourcescrub to Datasite and PlanHub to GrowthCurve Capital.
What does Mainsail Partners buy?
Mainsail Partners buys into bootstrapped B2B software companies with roughly $4 million or more in recurring revenue and little or no prior institutional capital. The firm stated a target range of $4 million to $25 million in annual revenue when it raised Fund V, and a typical investment of $30 million to $60 million when it raised Fund VI.
| Criterion | Mainsail’s stated profile | Source |
|---|---|---|
| Revenue at investment | $4M to $25M annual revenue, at least $4M recurring | Fund V announcement, 2020 |
| Typical investment | $30M to $60M | Fund VI announcement, 2022 |
| Funding history | Bootstrapped, founder-led, little or no institutional capital | Firm website and fund releases |
| Sectors | Vertical SaaS, fintech, healthcare IT, infrastructure and security software | GrowthCap firm profile |
| Business model | B2B software with recurring revenue | Firm website |
| Geography | North America, from offices in San Francisco and Austin | Fund VII announcement, 2025 |
The 2025 vintage shows how vertical the thesis runs. Mainsail’s eight platform investments in 2025 covered hotel accounting, chiropractic practices, fire safety compliance, heavy equipment dealers, racquet clubs, specialty subcontractors, and ERP for metal finishing shops.
What has Mainsail Partners actually invested in?
Mainsail Partners made eight platform investments in 2025 and disclosed the check size on most of them, which is unusual transparency for growth equity.
| Company | What it does | Date | Disclosed investment |
|---|---|---|---|
| Steelhead Technologies | ERP for metal finishing and fabrication | 2025 | $84 million |
| CourtReserve | Racquet and paddle club management | 2025 | $54 million |
| Inn-Flow | Hotel management and accounting software | 2025 | $45 million |
| FlyntLok | Heavy equipment dealer management | 2025 | $36 million |
| FieldFlo | Software for specialty subcontractors | 2025 | $35 million |
| Life Safety Inspection Vault | Fire and life safety compliance | 2025 | $28.7 million |
| ChiroHD | Chiropractic practice management | 2025 | $26 million |
| SmartMoving | Software for moving companies | August 2022 | $41.5 million |
Mainsail portfolio companies also acquire. The portfolio completed nine add-on acquisitions in 2025, including Innergy buying Microvellum and Inspect Point buying FireCAD. Exits run through strategics and larger sponsors: Fullbay took a new investment from JMI Equity in July 2024, with Mainsail reinvesting alongside.
What does Mainsail Partners typically pay?
Mainsail Partners discloses investment amounts but not valuations, and no purchase multiple for any Mainsail deal is public. An investment amount is not a price. A $45 million check can buy 40 percent of one company or 80 percent of another, and only the implied enterprise value tells a founder what the business was priced at.
Windsor Drake’s published valuation research places private equity platform acquisitions of SaaS companies at 4 to 6 times revenue, with add-on acquisitions at 3 to 5 times revenue. Where any individual Mainsail deal lands against that band is not public. The same research finds strategic acquirers pay 15 to 30 percent premiums over financial buyers, which is why the difference between strategic buyers and financial buyers matters when a growth equity firm is the only bidder.
A founder holding a single Mainsail term sheet has one data point and no market. That is a structural pricing problem, not a comment on Mainsail’s conduct.
How does Mainsail Partners find companies?
Mainsail Partners sources deals through direct, relationship-based outreach to founders of bootstrapped software companies. The firm added a Vice President of Business Development in 2020 and has grown its sourcing function alongside each fund. Outreach typically starts years before any transaction conversation.
Direct sourcing exists to reach founders before a competitive process exists. A founder who takes a Mainsail call usually has no adviser engaged and no competing bid in hand. That asymmetry favors the buyer regardless of how friendly the conversation feels.
What does a Mainsail Partners approach look like?
The typical sequence is a warm email or call, a get-acquainted conversation, a request for financial metrics, and then a term sheet with an exclusivity clause. Growth equity buyers ask for 30 to 90 days of exclusivity as a standard opening position. Windsor Drake recommends founders concede no more than 30 to 45 days.
Mainsail’s outreach is professional and often genuinely flattering, because the team has studied the company before calling. Flattery is not a valuation. A founder who wants to engage without giving up position should start with Windsor Drake’s guide to handling an unsolicited offer and the wider offer-received resources.
What is life like after selling to Mainsail Partners?
Mainsail Partners runs one of the larger operating groups in lower-middle-market growth equity. The firm reports a Growth Team of more than 40 people, roughly 1,500 engagements with portfolio companies each year, and a Mainsail AI Labs group launched in 2025. Annual portfolio summits cover CEOs, product and technology, fintech, talent, and finance leaders.
Founder accounts published by the firm are positive, and Inc. named Mainsail to its 2022 list of founder-friendly investors. One portfolio founder described a purpose-built team with deep operational experience working side by side on roadmap planning. Independent accounts not published by Mainsail are scarcer, so founders should request references beyond the firm’s own materials.
Who else competes with Mainsail Partners for bootstrapped SaaS companies?
The buyer pool for bootstrapped vertical SaaS is crowded. Level Equity runs a similar outbound model from New York, Serent Capital targets founder-led B2B software from the same two cities as Mainsail, and PSG buys platforms and add-ons at higher volume from multi-billion-dollar funds. Permanent-hold consolidators such as Volaris and Valsoft compete for the same vertical software assets with a very different ownership model. Windsor Drake profiles the full buyer set in its guide to private equity firms that buy SaaS companies.
What would a competitive process change?
The Proprietary Discount is the gap between what a serial acquirer pays in an unbanked bilateral negotiation and what the same business clears in a competitive process. Windsor Drake measures that bilateral-versus-competitive gap at 15 to 25 percent of enterprise value. Mainsail is a disciplined repeat buyer, and repeat buyers price sharpest when nobody else is bidding.
A competitive process changes the denominator. Windsor Drake opens every mandate with a buyer universe of 150 to 300 potential acquirers, which turns one term sheet into a market. A founder weighing whether to hire representation should start with whether you need a banker.
If Mainsail Partners has already approached you, Windsor Drake’s Approach Response engagement runs a competitive process alongside the live offer in 4 to 6 months.
Questions founders ask
Is Mainsail Partners private equity or venture capital?
Mainsail Partners is a growth equity firm, a category of private equity. Mainsail invests $30 million to $60 million in bootstrapped software companies that already have at least $4 million in recurring revenue, rather than backing pre-revenue startups the way a venture firm would.
How much does Mainsail Partners invest per deal?
Mainsail stated a typical investment of $30 million to $60 million when it raised Fund VI in 2022. Disclosed 2025 checks ranged from $26 million for ChiroHD to $84 million for Steelhead Technologies.
Does Mainsail Partners buy 100 percent of companies?
Mainsail structures deals as growth equity investments rather than full buyouts, and founders typically retain meaningful equity and continue running the company. The exact ownership split in any Mainsail deal is negotiated privately and is not published.
What multiple would Mainsail Partners pay for a SaaS company?
No Mainsail purchase multiple is public. Windsor Drake’s published valuation research places private equity platform acquisitions of SaaS at 4 to 6 times revenue and add-ons at 3 to 5 times revenue. A founder cannot benchmark a single private offer without creating a market around it.
Should I take a call from Mainsail Partners?
Taking an introductory call costs little, and Mainsail’s team is well prepared and professional. Sharing detailed financial metrics before deciding whether to run a process costs a lot, because the data shapes the buyer’s price before any competition exists.
How long does Mainsail Partners hold its investments?
Mainsail does not publish a target hold period. Mainsail invests from closed-end funds that must return capital to limited partners, and 2025 exits such as Sourcescrub to Datasite and PlanHub to GrowthCurve Capital show the portfolio turns over through sales to strategics and larger sponsors.
Does Mainsail Partners work with sell-side bankers?
Mainsail sources most opportunities directly, but growth equity firms routinely participate in banked processes and represented deals still close. A founder hiring an adviser does not lose access to Mainsail; the adviser changes the price-setting mechanism from one bid to many.
Last reviewed July 28, 2026 by Jeff Barrington, Founder and Managing Director, Windsor Drake. Content on this page may be cited with attribution and a link to https://windsordrake.com/acquirers/mainsail-partners/