Fiduciary vs Reg BI Best Interest: How to Tell the Difference

The difference between fiduciary vs Reg BI comes down to one thing: the legal duty your advisor owes you. A fiduciary under the Investment Advisers Act is legally obligated to act in your best interest. A broker operating under Regulation Best Interest (Reg BI) follows a different, generally lower standard. Both can sound similar in a meeting. The distinction only shows up when the advice could go one of two ways, and one of those ways pays the advisor more.

If you are a business owner or high earner who has been pitched before, this distinction matters more than any single product or rate of return. Here is how to tell which standard your advisor actually follows, and why it shapes everything from your tax plan to your retirement income.

What does fiduciary vs Reg BI actually mean?

These two terms describe two different legal frameworks created by two different sets of rules. They are not interchangeable, even though the marketing language around them often blurs together.

Fiduciary standard (Investment Advisers Act of 1940)

A duty that requires a registered investment adviser to act in the client's best interest at all times, to disclose and manage conflicts of interest, and to put the client's interest ahead of its own. It applies across the ongoing advisory relationship.

Best interest obligation under Reg BI

A standard adopted by the SEC in 2019 that applies to broker-dealers when they make a recommendation to a retail customer. It requires the broker to act in the customer's best interest at the time of the recommendation and to disclose conflicts, but it is a different and generally narrower duty than the fiduciary standard.

The older term you may have heard, "suitability standard," is outdated. Reg BI replaced it for brokers in 2020. So if an advisor or a piece of content references suitability, that language is behind the times.

The gap between the two standards is not about honesty. It is about scope and timing. A fiduciary duty follows the whole relationship. A best interest obligation under Reg BI attaches to a specific recommendation.

Why the difference matters for business owners

For someone with a straightforward situation, the practical difference may be small. For a business owner with $5M+ in revenue, a coming liquidity event, and a tax picture that touches every other decision, the difference compounds.

Consider how the two standards behave when there is a fork in the road:

None of this makes brokers dishonest or fiduciaries flawless. Plenty of skilled professionals operate under Reg BI. The point is that you should know which framework governs the advice you are receiving, because that framework shapes how conflicts get handled when your interests and the advisor's compensation point in different directions.

Is my advisor a fiduciary? Three ways to check

You do not have to guess. There are concrete ways to find out which standard applies.

1. Read Form CRS

Every firm that serves retail investors must give you a Form CRS (Client Relationship Summary). It is short by design and states whether the firm is an investment adviser, a broker-dealer, or both. It also lists conflicts of interest and how the firm is paid. You can find these filings publicly through the SEC and through FINRA's BrokerCheck.

2. Read Form ADV

If the firm is a registered investment adviser, it files a Form ADV. Part 2 is written in plain language and describes services, fees, conflicts, and disciplinary history. This is where you learn how the firm gets compensated and where conflicts may exist.

3. Ask the question in writing

The simplest move is also the most revealing: ask the advisor, in writing, whether they are acting as a fiduciary for the advice you are receiving, and to confirm it in an email or engagement document. A fiduciary relationship is comfortable putting that commitment on paper. If the answer comes back vague, that tells you something.

One clean question cuts through most of the confusion: "For the advice you are giving me right now, are you acting as a fiduciary, and will you put that in writing?"

Can one person be both?

Yes. This is the part that surprises most people. Many professionals are "dually registered," meaning they can act as an investment adviser representative in some moments and as a broker in others. The same trusted person across the table may switch capacities depending on what they are recommending.

That is not inherently a problem, but it means the title on a business card does not settle the question. What matters is the capacity they are acting in for a specific piece of advice. A dually registered professional recommending a commission product may be operating under Reg BI for that recommendation even if they manage other assets as a fiduciary.

This is exactly why coordination matters. When tax strategy, investments, insurance, and estate decisions all touch each other, you want to understand the standard governing each piece, and you want one relationship watching how the pieces fit together. We cover that integration in our overview of proactive tax planning, where the same fiduciary-first thinking applies to reducing what you may owe next year.

Where Anchor stands

Anchor operates as a fiduciary under the Investment Advisers Act for its advisory relationships, which is a higher standard than the best interest obligation under Reg BI. We treat the question of which standard applies as something you deserve to understand, not something to talk past.

Our role is strategy and coordination across tax, investments, insurance, retirement, and estate planning. We do not file your taxes and we do not give legal advice. You keep your own CPA and attorney for those functions, and we work alongside them so the strategy holds together. That coordination is the point, especially for decisions like when to claim Social Security or how to plan around the large healthcare costs many retirees face, where one decision quietly affects another.