Connecting Fidelity, Vanguard or Schwab to an AI Assistant
Last updated August 2026
Short answer
Each broker connects separately and takes about a minute, and the case worth setting up is all of them at once. Holding accounts across two or three of Fidelity, Vanguard and Schwab is extremely common, usually a workplace plan at one and a taxable account at another, and it is exactly the situation where single-account analysis is least useful: concentration, fund overlap, asset location and true cost are all properties of the whole portfolio, not of any one account. Connections are read-only for holdings, and your broker login never leaves your broker. Walnut is informational and is not an investment adviser.
These three turn up together more than any other combination, and usually not by design: a plan from an old job, an IRA opened somewhere convenient, a taxable account started years later. Each looks fine on its own statement. The interesting questions only exist once you can see them side by side, which is the actual reason to connect rather than the convenience of not typing.
Why fragmentation defeats most analysis
| What you want to know | Why one account cannot tell you |
|---|---|
| Concentration | Each account looks reasonable alone. Combined, one company can be a quarter of everything |
| Fund overlap | Two funds at two brokers can hold substantially the same companies, invisibly |
| Asset location | Cannot be assessed at all without seeing the taxable and sheltered accounts together |
| True cost | A weighted expense ratio across a portfolio you can only see a third of is not a number |
| Performance | Judging one account tells you about that account, not about your money |
The first row is the one that catches people. Employer stock in a workplace plan, a technology fund in an IRA, and a broad index fund in a taxable account can each be sensible, while the combination is a quarter of your money in the same handful of companies. Nothing about any single statement reveals that.
The three, and what is worth checking at each
1. Fidelity
The most common home for a workplace plan and a rollover IRA at the same time, so a Fidelity connection often brings in more than one account. Its own funds carry tickers you may not recognise from a fund name, which is exactly the case where look-through matters.
Step-by-step: connecting Fidelity.
2. Vanguard
Usually the index core of a portfolio, which makes overlap the interesting question rather than performance: several Vanguard funds are close cousins and a portfolio can be less diversified than the fund count suggests.
Step-by-step: connecting Vanguard.
3. Schwab
Often holds a taxable account alongside a retirement account, which is the pairing where asset location has something to say. It is also a common destination after a transfer in, so cost basis is worth checking once connected.
Step-by-step: connecting Schwab.
How to connect
Connect each broker inside Walnut once, then add the connector to your assistant. The assistant reads whatever Walnut can see, so the order matters: brokers first, assistant second.
https://walnutinvest.com/api/connector/mcp
Setup guides: Claude or ChatGPT. For everything the assistant can and cannot see once it is connected, see what the connector is.
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.
The first four questions to ask once all three are connected
- “Across all my accounts, what share sits in my single largest company?” The number that fragmentation hides.
- “Do any of my funds across these brokers hold substantially the same companies?” Two broad funds at two brokers is the most common quiet duplication.
- “What is my weighted expense ratio across everything?” Meaningless per account and meaningful in total.
- “Which account should I rebalance in to avoid a tax event?” Only answerable once the sheltered and taxable accounts are both visible.
The account you will be tempted to leave out
There is almost always one: the old workplace plan from two jobs ago, small enough to feel irrelevant, or the account holding a single position you already know about. Leaving it out feels like a reasonable simplification and it is the most common way this analysis goes wrong.
The reason is that the excluded account is rarely random. It is usually old, which means it has had the longest to drift, and it frequently holds employer stock, which is the single most common source of unintended concentration. An analysis of everything except the account most likely to be concentrated will confidently tell you that you are diversified.
If an account is genuinely too small to matter, connecting it costs a minute and confirms that. If it turns out not to be small, you have found the thing you were looking for.
What connecting does not change
Your money does not move. Your accounts stay at Fidelity, Vanguard and Schwab, under the same logins, with the same statements and the same tax reporting. Nothing is transferred, consolidated or placed under management, and there is no percentage-of-assets fee, because nothing is being managed.
That is the difference between this and a robo-advisor, and it is worth being explicit because the two get confused. A robo-advisor would ask you to move these accounts to it and would then sell the holdings to buy its own allocation. A connector reads them where they are. See alternatives to a robo-advisor for the wider comparison.
What it still will not see
Accounts you do not connect, obviously, and also everything that is not a brokerage account: property, a pension outside these providers, a business, and a spouse's holdings. That last one matters more than people expect, because two individually sensible portfolios in one household can combine into something heavily overweight one employer or one sector.
It also does not know your tax position, so anything it says about selling is arithmetic rather than planning. Where that boundary sits is in what portfolio analysis can and cannot do.
FAQ
Should I bother connecting a small old account?
Yes, and it is the one most likely to matter. The account people leave out is rarely random: it is usually the oldest, so it has had the longest to drift, and it frequently holds employer stock, which is the most common source of unintended concentration. An analysis of everything except the concentrated account will tell you confidently that you are diversified.
Does connecting move my money?
No. Your accounts stay where they are, under the same logins, with the same statements and tax reporting. Nothing is transferred, consolidated or placed under management, and there is no percentage-of-assets fee because nothing is being managed. That is the difference from a robo-advisor, which would ask you to move the accounts and then sell the holdings.
Can it see accounts at other brokers too?
Yes, most major US brokerages connect for reading holdings. The value of the analysis scales with how much of the picture it can see, so there is no reason to stop at three, and the accounts left out are the ones most likely to be hiding what you were looking for.
Can I connect Fidelity, Vanguard and Schwab to an AI assistant at the same time?
Yes, and that is the case worth setting up. Each broker connects separately, and once all of them are linked the assistant reads them as one portfolio. Holding accounts across two or three of these is extremely common, usually a workplace plan at one and a taxable account at another, and it is exactly the situation single-account analysis handles worst.
Why does connecting more than one broker matter?
Because most of what you would want to know is only visible across all of them. Concentration, fund overlap, asset location and true cost are properties of your whole portfolio, and each account can look sensible on its own while the combination is something nobody would have chosen.
Is the connection read-only?
For holdings, yes. The assistant reads positions and prices and cannot place an order or move money. Trading through Walnut happens in Walnut's own assistant on the web, with an explicit preview and confirmation for every order.
Does the assistant get my Fidelity or Vanguard login?
No. Your broker login stays with your broker: Walnut connects through a secure connection and never sees or stores those credentials, and the assistant authenticates to Walnut rather than to your broker. Nothing in the chain hands an AI a brokerage password.
Can it see my 401(k) as well as my brokerage account?
It depends on how the plan is held and whether the provider exposes it. A workplace plan administered by the same firm as your IRA sometimes comes through with it and sometimes does not. Connect and check what appears rather than assuming either way, because the answer varies by plan rather than by broker.
What if my accounts are at other brokers too?
Connect those as well. Most major US brokerages connect for reading holdings, and the value of the analysis scales with how much of your picture it can see. The accounts you leave out are the ones most likely to be hiding the concentration you were looking for.
Will it show my cost basis?
Where the broker supplies it. Basis is the field most likely to be missing or wrong after a transfer between brokers, so if you have moved an account recently it is worth checking what arrived rather than trusting the first number you see.
Which assistant should I use for this?
Claude or ChatGPT are the two we verify, and both use the same connector URL, so the choice is about which assistant you prefer rather than which sees more. Setup takes about two minutes in either.
Connect your broker to an AI assistant
Step-by-step guides for each major broker, plus the general setup guides for ChatGPT and Claude, which brokers have an AI assistant built in, and Walnut's MCP connector.
Related articles
Walnut is informational and is not an investment adviser, and nothing here is investment advice. Broker support and which account types come through vary by provider and by plan, and change; connect and check what appears rather than relying on any list.