The way you pay your financial advisor matters more than most people realise. A seemingly small difference in fee structure can cost — or save — you hundreds of thousands of pounds over a lifetime. In this guide, we compare flat-fee financial advisors with percentage-based (AUM) advisors so you can make an informed choice.
How Percentage-Based (AUM) Fees Work
The traditional model charges a percentage of your assets under management (AUM) — typically 0.5% to 1.5% per year. This means the more wealth you accumulate, the more you pay, even if the work your advisor does stays the same.
- £250,000 portfolio at 1%: £2,500/year
- £500,000 portfolio at 1%: £5,000/year
- £1,000,000 portfolio at 1%: £10,000/year
Over 25 years, a 1% fee on a £500,000 portfolio with 5% real growth consumes roughly £200,000+ of your wealth. Use our free fee calculator to see the exact impact on your numbers.
How Flat-Fee Advisors Work
Flat-fee advisors charge a fixed amount for their services — either per plan, per hour, or as an annual retainer. The fee doesn't change based on your portfolio size.
- One-off financial plan: £500 – £3,000
- Annual retainer: £1,500 – £5,000/year
- Hourly consultation: £150 – £400/hour
The key difference: your fee stays the same whether you have £200,000 or £2,000,000 in investments.
Side-by-Side Cost Comparison
Let's compare the 25-year cost for a £500,000 portfolio growing at 5% real return:
- 1% AUM advisor: ~£204,000 in lost growth (fees compound against you)
- Flat-fee retainer (£3,000/year): £75,000 total over 25 years
- Savings with flat fee: ~£129,000 more in your pocket
The gap widens dramatically with larger portfolios. At £1,000,000, the AUM model costs roughly £408,000 over 25 years — more than five times the flat-fee alternative.
When Percentage Fees Make Sense
To be fair, the AUM model isn't always worse. It can work in your favour in specific situations:
- Small portfolios (under £100,000): A 1% fee is only £1,000/year — potentially less than a flat-fee retainer
- Comprehensive ongoing management: If your advisor handles tax planning, estate work, insurance reviews, and rebalancing continuously
- Behavioural coaching: Some investors need a human to stop them panic-selling in downturns — and the ongoing relationship of AUM creates that accountability
When Flat Fees Save You More
For most people with portfolios above £250,000, flat fees are significantly cheaper:
- You're a buy-and-hold investor who doesn't need frequent portfolio changes
- You want a one-off plan rather than ongoing management
- Your portfolio is growing — AUM fees grow with it, flat fees don't
- You use low-cost index funds and don't need active stock picking
The rise of robo-advisors and free planning tools means the ongoing management piece is increasingly automated, making the AUM premium harder to justify.
The Hidden Problem With Both Models
Here's what most fee comparisons miss: neither model guarantees the advice is actually good.
The most expensive advisor in the world can't help you if they optimise for the wrong goals. As we explored in why most financial plans fail, the missing ingredient isn't better portfolio management — it's purpose.
Before choosing a fee structure, ask yourself: do I even know what this money is for? Our free life purpose assessment helps you answer that question first.
How to Find a Good Flat-Fee Advisor
If you decide flat-fee is right for you, here's what to look for:
- Fee-only fiduciary: They should be legally required to act in your best interest, not earn commissions on products
- Transparent pricing: The fee should be published on their website — no "contact us for pricing"
- Scope clarity: Know exactly what's included (investment plan, tax strategy, insurance review, etc.)
- No AUM upsell: Some advisors offer a "flat fee" initial plan but then push you into ongoing AUM management
A Smarter Approach: Combine Free Tools With Occasional Expert Advice
The most cost-effective strategy for most people in 2026:
- Start with purpose: Use FYP's free tools to define what your money is actually for
- DIY the basics: Use free calculators, budgeting apps, and planning tools for everyday financial management
- Hire flat-fee help for complexity: Pay a flat-fee advisor for specific situations — tax planning, estate work, or major life transitions
- Review annually: Check your retirement checklist and adjust as needed
This approach gives you expert guidance when you need it without the ongoing wealth erosion of percentage-based fees.
The Bottom Line
If your portfolio is above £250,000 and you don't need daily hand-holding, a flat-fee advisor will almost certainly save you money over time. But the most important financial decision isn't how you pay your advisor — it's making sure your plan reflects the life you actually want to live.
Start with purpose, plan with clarity, and pay only for what you need.