Most deals clear investment committee on the strength of the model.
Very few deliver because the operating reality never quite matches the slide deck.
The firms that win the next decade in PE will do it the hard way: through integration discipline, operational finance, and intelligent use of AI—while everyone else is still relying on yesterday’s playbook.
This Substack is written for boards, CEOs, CFOs, and investors who care about what happens after the term sheet is signed.
Why subscribe?
I write from the vantage point of an operational finance leader who has lived inside PE-backed industrial and defense businesses building reporting from nothing, integrating acquisitions, and recently using AI as a practical tool (not just a buzzword).
You’ll see recurring themes:
Integration as a core capability, not a post‑close project.
Operational excellence and a relentless focus on value creation for Customers as the path to value creation for investors.
AI as augmentation for finance, not as a replacement for people or judgment.
Reporting and FP&A that facailitates capital allocation.
Treating AI like any other investment: risk‑adjusted return, customer impact, and competitive advantage.
If you sit on a Board, run a PE fund, or operate inside a portfolio company, the goal is simple: help you create value as the business environment changes rapidly.
The Big Changes
Interest rates have changed the economics.
PE exits are getting harder.
Integrations no longer can be just surface level (logos and simple org chart changes).
AI will compress timelines: good operators will compound faster, and weak integrations will fail sooner.
About Timothy O’Reilly, FCA
I’m a Chartered Accountant and CFO/Operator focused on M&A integration, operational finance, and AI-enabled transformation in PE-backed and growth businesses.
In portfolio companies, I’ve:
Led integrations of multiple acquisitions totaling over $350m in enterprise value, with consistent revenue growth and meaningful margin expansion
Taken a near‑insolvent business from loss to profit within 12 months, then steered it through examinership and an orderly wind‑down when a sale failed
Built lender‑grade reporting and planning in environments with fragmented systems, no close discipline, and no historic covenant reporting—often before touching ERP or FP&A tools at all
Earlier, I founded and grew a high profile accounting and advisory firm in Ireland from €0 to €3.9m+ in revenues and 33 people, now part of EisnerAmper Ireland. That decade of building, fixing, and advising across hundreds of clients is where most of my pattern recognition comes from.
How I think about AI and operations
A lot of AI commentary is abstract. Mine isn’t.
I use AI directly in the work: mapping charts of accounts, building and testing FP&A models, interrogating financials, and pressure‑testing scenarios
I treat every AI initiative as a capital allocation decision: does it improve customer outcomes, revenue, margins, risk, or competitive advantage? If not, it’s noise, not strategy
I focus on foundations first: clean reporting, solid data architecture, and board‑ready models. AI just amplifies whatever is already in place.
I also care deeply about where and how AI runs. In regulated and sensitive environments (defense, ITAR, pensions), local and sovereign models are often the only responsible option, and they’re getting better by the month.
Personal Passions
Outside the boardroom and finance stack, I build drones, submersible ROV’s, and 3D‑printed parts in my ‘man cave’. That matters because many of the businesses I work with are industrial, engineering, or defense. When I sit with technical teams it’s a practical conversation, not a theoretical one.
What I do through one137th
Through one137th, I work with PE-backed and growth-stage businesses, primarily industrial, defense, and engineering that are based in Ireland, the UK, and the US. Typical mandates include:
Post‑acquisition integration and reporting build‑out.
FP&A and “decision intelligence” infrastructure that boards can rely on.
AI strategy focused on finance and operations, with an emphasis on measurable impact and compliance in regulated environments.
Contact
email: timothy.oreilly@one137th.com
FCA (Chartered Accountants Ireland) | Harvard Business School | Dual Irish/US Citizen
