Interactive Brokers vs Marcus Invest: Which Is Better in 2026?

Prices checked October 2026. A price marked (Oct 2026) was read on the vendor's own pricing page; others are described without a number because we could not verify one.

Broad market access with AI-integration options and community-built MCP connectors. Best for advanced and international investors.

How it works: Interactive Brokers gives you broad global market access through professional platforms (like Trader Workstation) and a deep API. AI integration is possible by wiring tools to that API or using community-built MCP connectors, but there is no polished, official consumer AI assistant, so the AI layer is something you or a developer assemble.

In practice, Interactive Brokers’s AI AI-integration options (community MCP). It is a brokerage API for people building their own AI agent, best suited to advanced and international investors. On connecting an account: IBKR accounts. On execution: read + trade. Cost: brokerage fees.

One real limitation: Powerful but complex; AI connectors are mostly community-built.

Goldman Sachs' former automated investing service, closed in 2024 when its accounts moved to Betterment.

How it works: Marcus Invest used a questionnaire to set a risk level and invested in model ETF portfolios built by Goldman Sachs. Goldman Sachs closed it in 2024 and transferred the accounts to Betterment, so anyone who held one now has a Betterment account under Betterment's own pricing.

In practice, Marcus Invest’s AI discontinued in 2024. It is a robo-advisor (hands-off automated investing), best suited to former Marcus Invest clients checking where their account went. On connecting an account: no (holds your money at Marcus). On execution: not offered. Cost: discontinued; accounts moved to Betterment (2024).

One real limitation: Marcus Invest is closed: Goldman Sachs moved its accounts to Betterment in 2024, so the comparison that matters now is Betterment itself.

Category comes first. Interactive Brokers focuses on advanced and international investors (AI-integration options (community MCP)), and Marcus Invest on former Marcus Invest clients checking where their account went (discontinued in 2024). On broker connection they differ too: Interactive Brokers is “IBKR accounts” versus Marcus Invest at “No (holds your money at Marcus)”. That shapes everything downstream: how personal the answers are, where trades settle, and how much control you keep over individual positions.

Every tool gives something up for what it does well. Below is the give-and-take on each, so you can weigh the specific strengths against the limitations that come with them, beyond the headline category.

For AI investing tools, the distinction that matters most is whether the tool works from your actual, connected positions or reasons from something else: a separate account it manages for you, or the tickers and numbers you feed it. It decides how personal the answers can be, and where your money physically lives.

• Interactive Brokers: connects specific supported accounts. Interactive Brokers connects a defined set of accounts (IBKR accounts), so whether it can see your holdings depends on whether your money is at one of them.
• Marcus Invest: manages a separate account it holds. Marcus Invest does not read the brokerage you already use. It opens and holds a new account, then invests the money you move into it, so its view is limited to what sits inside Marcus Invest.

This is where they diverge most. One works from your real, connected account while the other does not, so if you want an assistant grounded in the exact positions you already hold, that gap is the thing to weigh first. This holdings-aware angle is the one Walnut is built around: it connects the brokerage you already use and reasons from your live positions, read-only by default, with any trades left for you to approve.

Each one wins a different job, so the answer depends on which job you need done.

• Choose Interactive Brokers if you want advanced and international investors. Its AI AI-integration options (community MCP), and it costs brokerage fees. It is built for advanced or international investors who want breadth and are comfortable with complex tools. Keep in mind: powerful but complex; AI connectors are mostly community-built.
• Choose Marcus Invest if you want former Marcus Invest clients checking where their account went. Its AI discontinued in 2024, and it costs discontinued; accounts moved to Betterment (2024). It is built for nobody opening a new account, since the service is closed; former clients should compare Betterment, where their account now sits. Keep in mind: marcus Invest is closed: Goldman Sachs moved its accounts to Betterment in 2024, so the comparison that matters now is Betterment itself.
• Choose Walnut if you want a keep, trim or exit read on the stocks you already own, and placing the trades you approve. It is an AI investing app that connects the broker you already use, and it costs free; Walnut Plus $9.99/mo on the web; no fee on assets.

Because they sit in different categories, this is not strictly either-or: some investors use one for advanced and international investors and the other for former Marcus Invest clients checking where their account went, and watch for overlapping costs.

Cost is easy to misread when two tools charge in different shapes, so compare the model, not just the number. Interactive Brokers: brokerage fees. Marcus Invest: discontinued; accounts moved to Betterment (2024). A percentage-of-assets fee scales with your balance, a flat subscription does not, and a “free” tier usually earns elsewhere (on cash, order flow, or premium upgrades), so the cheapest headline is not always the cheapest outcome for your situation.

Prices checked October 2026. Pricing and tiers change, so confirm the current numbers on each provider’s own site before you decide.

Walnut is an AI investing app, and it is the pick for a keep, trim or exit read on the stocks you already own, and placing the trades you approve (free; Walnut Plus $9.99/mo on the web; no fee on assets). It connects the brokerage you already use, read-only by default, gives each holding a keep, trim or exit read against the S&P 500, flags any position above a quarter of the portfolio, and places the trades you approve. You use it through its own assistant, or inside Claude or ChatGPT. See Walnut vs Interactive Brokers and Walnut vs Marcus Invest.