Senior Commercial Finance Manager - 12 month FTC

Flagstone is an online savings platform, reinventing how individuals, businesses, and charities manage, protect, and grow their cash. A diverse group of people, bound by a collaborative spirit, and shared purpose. Our unique culture is our pride and joy and our competitive advantage.

To revolutionise the savings market, we need to be at our best. High performance takes more than talent – it takes a culture of kindness, respect, and growth. We’re building a diverse, inclusive community, where your voice is heard and valued. With close support and room to develop, you can surpass even your own expectations.

We are currently keen to bring on board a Commercial Finance Manager. This is a 12-month fixed-term contract covering maternity leave, sitting within Flagstone's FP&A team and partnering directly with our Growth tribe and Sales and Marketing functions. It’s a role for someone who can bring financial rigour to commercial conversations and turn data into decisions.

As Senior Commercial Finance Manager, you’ll be the go-to finance partner for our Growth tribe, Sales and Marketing functions — owning the top-line forecast and bringing rigour and commercial insight to how Flagstone allocates capital for growth.

In this role, you will:

• Own and maintain the revenue forecast, building and evolving cohort models that capture customer acquisition, retention and lifetime value dynamics.
• Partner with Sales and Marketing to understand funnel performance, interrogate conversion metrics, and translate commercial activity into financial outcomes.
• Build and scrutinise business cases and ROI calculations for proposed investments, ensuring the product backlog reflects the highest-value bets for the business.
• Partner with the Growth tribe — challenging assumptions, shaping prioritisation decisions, and ensuring capital is being deployed where it will have the most impact.
• Provide regular top-line reporting and variance analysis to senior stakeholders, with clear narrative on performance drivers.
• Support the FP&A planning cycle with timely, accurate and insight-led inputs on revenue and growth.

We’re looking for someone who combines strong technical modelling skills with genuine commercial curiosity. You don’t just build the model — you understand what it’s telling you and you know how to land that message with a non-finance audience.

Must haves:

• Experience building revenue and cohort models, with a track record of owning top-line forecasting in a growth-oriented business.
• Ability to build compelling, rigorous business cases and ROI analyses to support capital allocation decisions.
• Prior experience partnering with Sales and Marketing functions, with familiarity of marketing funnel metrics and conversion analysis.
• Strong communication and influencing skills — comfortable engaging with senior stakeholders and cross-functional teams.

Nice to haves:

• SQL skills and comfort working in data-heavy environments.
• 5+ years of relevant experience in Commercial Finance, FP&A or Strategy.
• Experience with FP&A planning tools such as Anaplan or Pigment.
• Background in fintech, SaaS or other subscription/recurring revenue businesses.

How we reward you:

At Flagstone, the benefits extend beyond false gifts like 'fruit and snacks'. Instead, we invest in your health, wealth, and professional development. Here’s a selection of our benefits:

• Hybrid working - Spend at least 1 day a week with your team in our collaborative London office.
• Competitive bonus scheme - designed to reward and recognise high performance.
• Flexible benefits budget - a pot to fund meaningful benefits for you, whether it’s hormone or fertility testing, cancer screening, neuro-diversity coaching or something that matters for you.
• A range of salary sacrifice options to help you make tax efficient savings on electric cars, nursery schemes, home and tech goods.
• Around the World scheme - 3 months work from anywhere scheme.
• Mental wellbeing support – Access therapy and mental health sessions through Spill.
• Learning and development – £1,000 personal development budget to help you grow in your role.
• Private health care - Enjoy all the benefits AXA has to offer, including reduced gym memberships and medical history disregarded.
• Medical cash plan - To help you with the costs of dental and optical expenses.
• Life insurance and Income Protection- four times your annual salary for peace of mind.
• Matched pension contributions up to 5%.
• 25 days holiday - plus bank holidays, well-being days and volunteering days.
• Enhanced Parental Leave – enhanced maternity, paternity and adoption pay.

At Flagstone, we’re assembling a diverse team that defies our industry’s norms. Think this role could suit you? We encourage you to apply, no matter your background.