Combinely, an 'AI co‑worker' for accountants

London Business School alumnus Tom Invernizzi (MFA 2021) never imagined he'd go from balancing ledgers to building an AI startup.

First as an accountant/auditor at Deloitte, then as a student in London Business School’s MFA programme, and later as an investment banking analyst, Tom experienced the drudgery of repetitive tasks and “busy work” that accountants and finance professionals face daily.

"I found myself way too often doing data entry, reinventing the wheel with the same client email responses and chasing down documents at midnight," says Invernizzi. "It was frustrating, inefficient, and all too common. That frustration planted a seed of an idea in my mind."

Over time, and with the help of LBS’s entrepreneurship community, that idea grew into Combinely, an 'AI co-worker' for accountants. This is the story of how identifying a personal pain point, and getting support from LBS, led Tom to co-found a startup now scaling through Y Combinator.

Finding the problem: From LBS to a “lightbulb moment”

After earning his Master’s at LBS in 2021, Tom jumped into a tech-focused investment banking role. He loved the fast pace and client exposure, but quickly noticed a pattern. "Ninety-five per cent of my work was heavily manual. Whether I was an accountant or an IB analyst, I was spending hours emailing clients, answering the same 'quick questions', chasing people for missing paperwork, doing data entry and digging through old threads to remind myself of context."

The more he spoke with former colleagues and friends in accounting, the more he heard the same complaint. Historically, scaling an accounting firm meant hiring because little could be automated. But with seventy-five per cent of US Certified Public Accountants (CPAs) retiring in the next decade, there’s a growing supply problem and firms already can’t keep up. Something had to change. He began asking: 'what if we could automate the tedious bits of an accountant’s job, and what if AI could act as a 'co-worker', handling the manual work, such that a three or four partner firm, deploying proxy AI 'workers', might be able to manage thousands of clients better than teams of hundreds do today.

"I started bouncing the idea off anyone who would listen," says Tom. "Professors, LBS alumni, and former coworkers. With this idea in mind, I teamed up with my co-founder. Arthur Granacher, who wrote Shazam’s iMessage app in three weeks, used by more than two million monthly active users (MAUs), and then spent the following four years at Google DeepMind automating doctor workflows. We had the perfect tech and domain expertise!"

What Combinely does: An 'AI Coworker' for accountants

Today, Combinely is the AI coworker Tom wishes he had back when he started in the accounting profession. In simple terms, Combinely is an AI coworker for accountants that automates their workflows end-to-end. It proactively handles work from answering complex client queries to producing and reviewing deliverables.

Here’s what Combinely does for an accounting team today:

Learns from the past and deep contextualisation. AI coworkers build live profiles on three levels - client, accounting firm, and topic - learning how each team works and tailoring every workflow automation for each client.

Acts proactively. Combinely acts like an accountant. As soon as an email comes in, it gets to work without waiting to be told. By the time you open your inbox, you have deliverables ready for your review.

"We've cut the time spent on manual workflows by half. We’re starting with accounting, but will expand to investment banking and consulting. As AI blurs these roles, as the same data is used but with different outputs, Combinely will eventually replace those who work in this space," claims Invernizzi.

How the LBS Incubator helped turn an idea into a startup

A good idea is one thing, but turning it into an actual business is another. In 2024, as Tom was sketching out the concept for Combinely, and applied to London Business School's Incubator Programme. Getting into LBS’s incubator was a turning point. "The Incubator gave me structure, mentorship, and "a community of peers on the same journey," says Invernizzi.

The structured timeline and check-ins imposed by LBS's Incubator created a healthy discipline. Osman Haneef, the Senior Ventures Manager who runs the Incubator, made sure Tom set clear goals. "That accountability was crucial - it’s easy to get lost in your own head as a founder".

Second, the early feedback Tom got through LBS proved "super valuable". "As part of the Incubator, we regularly pitched our concept to mentors, professors, and fellow entrepreneurs. This peer feedback helped us refine our message and avoid building something nobody wanted. For instance, one of my incubator peers pointed out that our initial vision - 'AI for professional services' - was too broad and that we’d be smarter to pare down to a beachhead market. We took that advice to heart and focused completely on accounting firms (ignoring other professional services for now)."

The Incubator also provided Tom with a network of mentors and experts. "Through LBS, we connected with experienced entrepreneurs. Lastly, simply being back in the LBS environment was motivating. Working out of the LBS's Sussex Place main campus where the Incubator is housed, surrounded by other scrappy founders, created a vibe of focused execution. Sharing not just the free coffee and coworking space, but also tips on everything from finding pilot customers to managing stress."

From LBS to YC: Building at warp speed in Silicon Valley

Early 2025, Tom applied to Y Combinator, and a few months later, found himself in California as part of YC’s Spring ’25 batch. "It’s a brief mention in this story because we’re still just midway through that experience but being in YC is like strapping a rocket to your startup," says Invernizzi. "The pace of learning and building is intense, but the lessons from LBS have absolutely carried over. For instance, YC is all about “talk to users, build fast, and iterate”, which was exactly the habit we developed in the Incubator."

What’s next for Combinely

With LBS Incubator in the recent past, and YC Demo Day on the horizon, the road ahead for Combinely is exciting. "Our immediate focus," says Invernizzi, "is on expanding into more complex accounting workflows and onboarding more firms onto Combinely. So far, our pilot users have been mid-to-large-sized accounting firms that are tech-forward. Over the coming year, we’ll be scaling up to work with larger accounting firms across the UK and the US. We’re already in talks with a few regional firms who see AI as a way to differentiate their service."

Advice for aspiring LBS entrepreneurs

Tom Invernizzi. concludes: "Some personal advice for any LBS students or alumni thinking about starting a venture. Find a real problem that you have lived and breathed. For me, being an overworked accountant and investment banker showed me exactly what needed fixing. When you deeply understand a problem, it guides you to a solution people truly want. Next, make the most of the community around you. I wouldn’t be here without the feedback from professors, mentors, and friends from LBS who challenged my assumptions early.

"Most importantly, just start. You don’t need permission to tinker with an idea. Build a scrappy prototype, talk to potential users, see if the problem is as painful as you think. LBS is a fantastic sandbox for this - use it. That leap can be scary, but if you’ve done your homework and you’re passionate about the solution, it’s worth it."