What changes between the two models?
The fee formula affects how cost scales and may shape which recommendations create an economic tension. It does not tell you, by itself, whether the advice is good.
A known dollar amount
The fee is set for the agreed scope or service period. Ask whether it is fixed for the full term, when it can be revised, and what work would require a separate engagement.
A percentage of managed assets
The fee is applied to assets under management. As the managed balance changes, the dollar fee generally changes too. Ask which accounts are billed and whether breakpoints apply.
Advice, planning, and management
Either model may include financial planning and portfolio management—or only part of that work. The agreement and disclosure brochure define the service, not the label.
Other layers of cost
Fund expenses, trading or custody charges, insurance costs, and outside legal or tax work may be separate. Ask for the total expected cost, not only the adviser’s headline fee.
Where the tradeoffs show up
Cost can favor either model.
A flat fee can be more expensive for a household with fewer managed assets, while an AUM fee can be more expensive as a portfolio grows. Compare dollars at today’s balance and under a few reasonable future balances.
Scope matters more than the fee label.
Investment management alone is different from coordinating retirement dates, pension choices, Social Security, tax planning, health coverage, cash reserves, estate work, and portfolio withdrawals. Confirm the actual work and who is responsible for implementation.
Conflicts do not disappear.
An AUM adviser has an incentive to retain and grow managed assets. A flat-fee adviser has an incentive to set, renew, or expand a paid engagement. The question is whether the conflict is understandable, disclosed, and managed.
A disciplined comparison
- Write down the decisions you need help making—not just the accounts you own.
- Convert each proposed fee to dollars for one full year.
- List every service included and every meaningful exclusion.
- Identify product, fund, custody, transaction, and outside-professional costs.
- Read Form ADV and the advisory agreement before signing.
- Decide whether the service and access are worth the total cost to your household.
Questions worth asking
- What will I pay in dollars during the first year and a typical later year?
- Which assets or services are included in that calculation?
- What work is included beyond investment management?
- Under what circumstances can the fee increase?
- What recommendation would reduce the amount you are paid?
- Where can I read your fees and conflicts in Form ADV?
Primary sources
These official resources explain common adviser fee arrangements and the disclosures investors should review.