A long-oriented investment partnership built on the belief that exceptional businesses, held patiently and with conviction, compound quietly into something extraordinary.
Begin the ConversationWe study businesses the way a biologist studies organisms — asking not what they will earn next quarter, but whether they are built to survive and adapt across cycles. The companies worth owning are the ones with genuine adaptive advantages that compound quietly across decades.
The greatest enemy of a good investment outcome is often the investor themselves. We design a process that is systematic, checklist-driven, and emotionally disciplined — building infrastructure against the cognitive biases that quietly erode returns for those who ignore them.
Being right nine times and catastrophically wrong once is not a good record. We hold a deep respect for the asymmetry of ruin. Our goal is not to maximize returns in any given year — it is to still be compounding in year thirty.
Perennial Partners seeks to compound capital over long periods by owning a small number of exceptional businesses purchased at sensible prices — guided by the belief that the best partnerships are built on trust, transparency, and a shared commitment to thinking clearly over a very long time.— Investment Philosophy, Perennial Partners LP
Brett Thornton is the founder and general partner of Perennial Partners LP, managed through B. M. Thornton Partners LLC. He is a self-directed student of investing with a deep and ongoing commitment to understanding how businesses create durable value — and how investors can position themselves to benefit from that over the very long term.
Over a career spanning more than fifteen years, Brett has built and led high-performing sales and leadership organizations in the infrastructure of the modern electrical grid — at APC by Schneider Electric, Carbonite, Schneider Electric, and now ABB Electrification Services, where he serves as Director of Sales for the Western United States. This career has given him a hands-on familiarity with the energy transition — not as a thesis, but as something he lives and works within every day.
His investment education is self-directed, intensive, and rooted in the Buffett-Munger tradition of value investing, enriched by evolutionary biology, behavioral psychology, and a serious study of how great businesses are built and how they fail. He thinks in decades, acts with conviction, and believes that intellectual honesty — and a good checklist — are the foundation of every sound decision.
He lives in Oakland, California with his beautiful physician wife and their two daughters, Violet and Daphne, who are the long time horizon.
Years spent working inside the infrastructure of the energy transition have given Brett a working familiarity with how capital moves through the grid, what electrification actually looks like at the operational level, and which business models hold up under pressure. That context informs judgment — it doesn't define the portfolio, but it sharpens how we evaluate businesses operating within these forces.
We invest at the intersection of process and patience. Checklists, probabilistic thinking, and Stoic principles are not aspirational — they are the operating system. The ability to sit still when others panic, and act with conviction when others are paralyzed, is the edge that cannot be arbitraged away.
Our time horizon is not a quarter or a year — it is the arc of businesses built to thrive across technological and economic cycles, including the rise of artificial intelligence as a compounding force. We are patient because the math of compounding rewards patience above almost everything else, and because the people we invest for deserve nothing less.
Perennial Partners LP is structured in the tradition of the original Buffett partnerships — where the general partner's interests are fully aligned with those of the limited partners, and performance is the only honest basis for reward. We are building something small and deliberate, beginning with a close circle of trusted partners.
Perennial Partners LP is a California limited partnership managed by B. M. Thornton Partners LLC as general partner. Limited partners hold economic interests in the partnership and share in its long-term returns.
We invest in a small number of exceptional businesses with durable competitive advantages, purchased at prices that offer a reasonable margin of safety. We hold for the long term. We do not use leverage. We do not chase trends.
The partnership is structured to reward genuine performance above a hurdle rate. There is no incentive to generate activity. The general partner earns meaningfully only when limited partners earn meaningfully first.
We are beginning with a small group of trusted partners — friends, family, and those who know us well. If you've found your way here and share our values and our time horizon, we would genuinely welcome a conversation.
We are building something patient and purposeful, one partnership at a time. If this resonates with you — the philosophy, the time horizon, the way we think about business and the world — we would love to hear from you.
brett.thornton@bmthornton.comThis website is for informational purposes only and does not constitute an offer to sell or a solicitation of an offer to buy any securities. Perennial Partners LP is in formation. Past performance is not indicative of future results.