About
About Numminen Advisory
Numminen Advisory is a CFO practice in Helsinki, Finland. We work with internationally focused, investor-backed technology companies whose finance function has to handle more complexity than their size suggests, usually because the group has grown across borders faster than the finance function underneath it.
The practice
What we do
Numminen Advisory provides fractional CFO services on a monthly retainer, interim CFO cover for a defined period, and fixed-scope projects and diagnostics for investor-backed startups and international growth companies.
The project work concentrates on four areas: group consolidation and multi-entity reporting, funding and diligence readiness, audit readiness, and transfer pricing and intercompany arrangements.
The practice is typically engaged when a company is preparing for an investment round, has added a foreign subsidiary, is facing its first audit or a change of auditor, has lost its finance leader, or is carrying public funding alongside investor capital.
Who we are
Numminen Advisory is founded and run by Joanna Numminen.
Fifteen years in finance inside international technology companies, from audit at Deloitte in Warsaw through controller and finance director roles to a CFO seat. She was the first finance hire at Timgu, ran SOX compliance and US GAAP reporting at Groupon in London, managed accounts payable across eight offices and twelve currencies at Indeed in Dublin, and was business controller and NetSuite product owner at NAPA across Finland, China, Japan, Korea and the United States.
As financial director at ONEiO she ran IFRS, US GAAP and Finnish reporting concurrently, led the group consolidation, took the company through venture capital due diligence and implemented NetSuite. As group controller at Silo AI she built the global finance function from the ground up, led end-to-end group consolidation, and took the group through financial due diligence and post-deal integration when it was acquired by AMD. Since 2025 she has served as CFO of Altum Technologies, a venture-backed cleantech scaleup commercialising high-power ultrasound technology, where she leads finance, investor relations and corporate strategy.
The pattern across those companies is complexity out of proportion to size: multi-entity groups operating across Finland, the United States, the Gulf, the United Kingdom, Ireland and Poland, reporting under IFRS, US GAAP and local standards at the same time, funded through a mix of venture capital, public funding and debt.
Background
Deloitte, Warsaw
Trained in audit.
Timgu, London
Financial controller and first finance hire.
Groupon, London
SOX compliance and US GAAP reporting.
Indeed, Dublin
Accounts payable across eight offices and twelve currencies.
NAPA, Helsinki
Business controller and NetSuite product owner across Finland, China, Japan, Korea and the United States.
ONEiO, Helsinki
Financial director. IFRS, US GAAP and Finnish reporting run concurrently, group consolidation, venture capital due diligence, NetSuite implementation.
Silo AI, Helsinki
Group controller. Global finance function built from the ground up, end-to-end group consolidation, financial due diligence and post-deal integration in the acquisition by AMD.
Altum Technologies, Helsinki
Chief Financial Officer. Finance, investor relations and corporate strategy for a venture-backed cleantech scaleup commercialising high-power ultrasound technology across energy, marine and industrial markets.
Numminen Advisory, Helsinki/Remote
Fractional and interim CFO for startups and growing technology companies.
How we work
Fixed fees
Quoted against scope, before the work starts.
Written deliverables
Clear outcomes, in writing, that your team keeps.
Discreet financial leadership
Every call, every month.
With your accounting firm
We work with your accounting firm and in-house controllers, not instead of them.
Get in touch
Numminen Advisory Oy. Business ID 3658803-7. Runeberginkatu 44 A10, 00260 Helsinki, Finland.