AUM vs Flat Fee vs Hourly: What Each Model Quietly Encourages
Last updated August 2026
Short answer
Every fee model makes some advice cheaper for the advisor to give and some advice more expensive. A percentage of assets is reluctant about anything that shrinks the balance: paying off a mortgage, an annuity, gifts to children, spending more in early retirement. A flat retainer is neutral on all of that and mildly pulls toward lighter service in a demanding year. Hourly has the tightest link between payment and work, and its real cost is the questions you do not ask because the meter is running. Pick on the incentive first, then on the arithmetic. Walnut is informational and is not an investment adviser.
Comparisons of these three are usually price tables, and price is the part that changes with your balance rather than the part that changes with the model. What is constant is the pull each one exerts on the advice itself, and none of it requires anyone to behave badly.
Three models, and what each quietly encourages
1. Percentage of assets under management
Encourages: Keeping assets under management and growing them. Aligned with you on portfolio growth, which is the model's genuine strength, and it bills less after a decline, at the moment paying feels worst.
Structurally reluctant about: Anything that reduces the balance. Paying off a mortgage, buying an annuity, giving money to children, spending more in early retirement. All are sometimes right and all shrink the fee, and this pull operates without anyone being dishonest.
Fits: Smaller balances, where a percentage is genuinely the cheapest way to buy ongoing advice
2. Flat fee or retainer
Encourages: Efficiency, and taking on complexity only when the fee reflects it. Neutral on every balance-changing decision, which is the cleanest incentive position of the three.
Structurally reluctant about: Extra work inside a fixed price. A retainer creates a mild pull toward fewer meetings and lighter service in a demanding year, which is the mirror image of the AUM problem and considerably smaller.
Fits: Balances above roughly a few hundred thousand, and anyone who wants ongoing planning at a predictable price
3. Hourly
Encourages: Answering the question you asked, well, and stopping. The tightest link between payment and work performed of any model in the industry.
Structurally reluctant about: Nothing about your money, and mildly toward longer engagements, which is the standard critique of billing by time. It also creates a real problem in the other direction: you will hesitate to call, and the questions you do not ask are the cost of this model.
Fits: A defined question, an annual check-in, or a second opinion on a plan you already have
The reluctance under the first model is the most consequential thing on this page, because the decisions it touches are among the largest anyone makes. It is also the least visible, since nothing about it looks like a conflict in a meeting. Nobody says no; the subject simply arises less often than it should.
The arithmetic, which decides the rest
| Balance | How the models compare |
|---|---|
| $100,000 | 1% is about $1,000. Most retainers cost more, so the percentage usually wins |
| $250,000 | About $2,500. Roughly where the two models meet |
| $500,000 | About $5,000. A retainer for the same services is frequently less |
| $1,000,000 | About $10,000. The gap is wide enough that not asking is expensive |
| Any balance, one question | Hourly wins decisively. You are buying an answer, not a relationship |
The last row is the one people skip past. A great many people who hire an ongoing advisor had a single question, and buying a relationship to answer a question is how someone ends up paying a percentage for a decade because they were unsure once. See whether one percent is worth it.
Get a recommendation for your situation
Walnut is the AI that knows your portfolio: ask anything in plain English, research any fund, and get an honest second opinion. On the broker you already use, read-only, and you approve every trade. Walnut is not a registered investment adviser.
How to pick
| If this is you | Model |
|---|---|
| I want someone watching continuously | Retainer above a few hundred thousand, percentage below it |
| I have one decision to make | Hourly. Do not buy a relationship to answer a question |
| My main asset is income, not a balance | Subscription or hourly. A percentage of a small balance buys little |
| I am about to retire and start spending | Retainer. A percentage charges most just as the work peaks and the balance starts falling |
| I want someone to argue with me | Any ongoing model. The friction is the product, and it needs a relationship |
The fourth row deserves emphasis because it is the least intuitive. A percentage of assets charges you most in the year the balance peaks and least once it has been drawn down, while the planning work, withdrawal sequencing, Social Security timing, Roth conversions, Medicare thresholds, is heaviest exactly as the fee starts falling. See advisors for retirees.
The question that settles it in one sentence
Ask any advisor which advice their fee model makes expensive for them to give. It is an unusual question and the answer is revealing in both directions. Someone who has thought about it will name the pull on their own model and describe how the firm handles it, which is what managing a conflict actually looks like. Someone who says their model has no such pull has told you either that they have not thought about it or that they would rather not, and both are useful to know before you sign anything.
Related: how advisors get paid, and flat-fee advisors.
FAQ
What is the difference between AUM, flat fee and hourly advisors?
A percentage of assets charges on what you hold, a flat fee charges a set amount regardless of balance, and hourly charges for time spent. The more useful difference is the incentive each creates: what advice becomes cheaper for the advisor to give and what advice becomes expensive.
Which advisor fee model is cheapest?
It depends on balance and on how much advice you need. A percentage is genuinely cheapest at smaller balances, a retainer usually wins above roughly a few hundred thousand dollars, and hourly is cheapest by a wide margin if you only have one question.
What is the problem with AUM fees?
The model has a standing reason to prefer your assets stay under management, so it is structurally reluctant about advice that shrinks the balance: paying off a mortgage, buying an annuity, giving money to children, spending more in early retirement. Each is sometimes right, and the pull operates without anyone being dishonest.
Are flat-fee advisors better?
They are cleaner on incentives, since a retainer is neutral about every balance-changing decision, and they are usually cheaper above a few hundred thousand dollars. The mild pull runs the other way, toward lighter service in a demanding year, which is the mirror image of the AUM problem and much smaller.
What is the downside of hourly advice?
You will hesitate to call. The questions you do not ask because the meter is running are the real cost of the model, and they are invisible. It also means nobody is monitoring anything between sessions, which is fine for a defined question and not for ongoing oversight.
At what balance does a flat fee beat 1%?
Usually somewhere in the low hundreds of thousands, depending on the retainer quoted and what it includes. At a hundred thousand the percentage is about a thousand a year and most retainers cost more; at a million it is about ten thousand for work that is rarely ten times greater.
Can I combine models?
Yes, and it works well. A cheap automated core for the portfolio plus hourly advice when something specific arrives covers most people's actual needs, and it costs a fraction of an ongoing percentage relationship. Some planners will also do an annual review as a fixed project.
Which model should someone approaching retirement use?
A retainer deserves serious consideration, because a percentage charges most in the year the balance peaks and least once it is drawn down, while the work is heaviest exactly as the fee starts falling. That is close to backwards for someone about to start spending their portfolio.
Related articles
Walnut is informational and is not an investment adviser, and nothing here is investment advice. Dollar figures are arithmetic on a stated percentage rather than quotes, and what any firm charges varies by service level and complexity.