ChatGPT vs Claude vs Perplexity vs Copilot for Investing (2026)

The fastest way to see the split is dimension by dimension. The standout row is the one they all share: “sees your real portfolio” is No for every one of them, because they are general assistants with no connection to your brokerage. After that, they diverge on live data, citations, reasoning depth, and math.

Capabilities and pricing change, and the “with browsing on” or “with code tool” qualifiers matter: ChatGPT and Claude only fetch live prices when their search tool is active, while Perplexity and Copilot ground answers in the web by default. Verify the current feature set on each provider's site.

Each assistant below is described the same way: what it is, its strengths for investing, its weaknesses, who it suits, and one honest limitation. They split by job rather than by an overall ranking, because the right one depends on the question you are asking.

There is no single best AI for investing research, because “research” covers different jobs and each assistant leads in a different one. Match the tool to the question:

• Current facts and quotes with sources. Perplexity wins. Live web search and an inline citation on almost every claim are its default, and its Finance view surfaces current prices, fundamentals, and news for a ticker. It is the one to reach for when you need today's number and want to see where it came from.
• Reading and reasoning over long documents. Claude wins. Its long-context strength means it can take a full 10-K, an earnings transcript, or a prospectus and reason across the whole thing without losing the thread, and its tone flags uncertainty instead of bluffing.
• All-round help and reliable calculations. ChatGPT wins. It is the strongest generalist for learning, drafting, and brainstorming, and its code-interpreter sandbox runs real Python, so allocation and percentage math is computed rather than guessed when you ask it to use the tool.
• Spreadsheet modeling and a Microsoft workflow. Copilot wins. If you already model a portfolio in Excel and live in Windows and Edge, grounded answers plus spreadsheet help in one place is its edge.

The honest takeaway: many investors use more than one, gathering cited facts in Perplexity, reasoning over them in Claude or ChatGPT, and checking the math in a code tool or Excel. None of them, used alone, can do the one thing that makes the analysis about you rather than a generic example.

Math reliability comes down to whether the tool computes or guesses. Large language models predict text, so when they do arithmetic in prose they can get a percentage, a position size, or an allocation subtly wrong while sounding certain. The fix is making them run real calculations:

• ChatGPT is most reliable when you ask it to use its code (Python) tool, which executes actual arithmetic rather than predicting the answer.
• Copilot is reliable inside Excel, where the spreadsheet does the computing and Copilot helps build the formulas.
• Perplexity tends to pull numbers from retrieved sources, which is safer than freehand math but only as good as the source.
• Claude reasons carefully and flags uncertainty, but in pure prose it can still slip on arithmetic, so verify anything that drives a decision.

For any number that touches real money, the rule across all four is the same: have the tool compute it, then check it. A confident wrong figure is the most dangerous output an AI assistant can give an investor.

No, and this is the single most important thing to understand. ChatGPT, Claude, Perplexity, and Microsoft Copilot are general assistants with no connection to your brokerage. They only know what you type or paste into the chat. That has three consequences for investing:

• The analysis is generic. Ask any of them “is my portfolio too concentrated?” and the answer is about a made-up example, because the tool has no idea what you actually hold.
• You become the data pipe. The only way to make the conversation specific is to describe or paste your positions by hand, which is tedious, error-prone, and instantly out of date.
• They cannot act. With no link to a broker, none can place a trade, rebalance, or even confirm a current position. They can describe a plan, not execute one.

This is not a flaw to be fixed inside ChatGPT or Claude; it is what a general assistant is. The gap is closed by giving the assistant access to your real account, which is a different kind of tool.

Every comparison above ends at the same wall. The four assistants differ on live data, citations, reasoning, and math, but they are identical on the row that matters most for a real investor: none can see what you actually own. Until that changes, every answer is about a hypothetical, not your portfolio.

The way to close the gap is to connect your brokerage so the assistant works on your real positions. That is the job of a connected tool. Walnut, the site you are reading, links your existing brokerage through SnapTrade (a regulated account aggregator) and lets you keep talking through Claude, ChatGPT, or a built-in assistant, now about your actual holdings with live prices instead of a made-up example. The connection is read-only by default, every trade needs your explicit approval, and you keep the broker you already use.

To be upfront, since this is our site: Walnut is not a general AI assistant and does not try to out-reason ChatGPT or out-cite Perplexity. It sits underneath them, as the connection that gives the assistant a view of your real account. Its dashboard frames each holding's return against the S&P 500 and classifies it as outperforming, in line, or lagging, alongside momentum and concentration reads. Because broker feeds rarely pass cost basis, Walnut frames returns as window returns rather than realized profit and loss, and says so. Walnut is not an investment adviser. If you want the mechanics, see how to connect your brokerage to an AI assistant.

The quickest way to decide is to match the assistant to the job in front of you, not to crown one overall. No single tool is best at everything, and the strongest setup usually uses more than one.

• You want today's facts with sources. Perplexity, for live quotes, recent news, and a citation on every claim you can click through to verify.
• You want to read a long filing or transcript closely. Claude, for long-context reasoning that holds the whole document at once.
• You want an all-rounder and trustworthy math. ChatGPT, for learning, drafting, and calculations run through its code tool.
• You live in Excel and Microsoft 365. Copilot, for grounded answers plus spreadsheet help where you already work.
• You want the conversation to be about your actual holdings. None of the four alone. Connect your broker through a tool like Walnut so the assistant works on your real positions, read-only by default, with any trade you approve.

Just as importantly, Walnut is the wrong tool for several investing jobs, and one of the general assistants (or a different product) fits better:

• You only want to learn or brainstorm with no money on the line. ChatGPT or Claude alone is enough; there is nothing to connect yet.
• You want fast, cited research on a ticker or the market. Perplexity is purpose-built for that, with sources on every claim.
• You want to model scenarios in a spreadsheet. Copilot inside Excel is the natural fit.
• You do not want to connect a brokerage at all. Walnut sits on top of a real account, so it needs one; a general assistant you paste holdings into would suit better.
• You want a one-shot risk score and recommendation report. A dedicated analyzer like PortfolioPilot delivers that format; see the best AI portfolio analyzers roundup.

From a connected account you can dig into a specific stock, an ETF you hold, or a theme you want exposure to.

For investing, ChatGPT, Claude, Perplexity, and Microsoft Copilot are not really competing for one crown; they win different jobs. Perplexity owns current, cited research. Claude owns deep reasoning over long filings. ChatGPT is the best all-rounder and the most reliable for math through its code tool. Copilot fits the Excel and Microsoft 365 crowd. But every one of them shares the same hard limit: it cannot see your real portfolio, so its analysis is about a hypothetical until you give it access to your account. Connecting your brokerage through a tool like Walnut is what turns any of them from a generic tutor into an assistant that works on what you actually own, read-only by default, with every trade you approve. None of these tools, Walnut included, is an investment adviser.