How to check how much two ETFs overlap with an AI agent: QQQ vs XLK

All outputs are real tool calls to the Equibles MCP server from 21 October 2026, trimmed.

Owning QQQ and XLK feels like holding two funds. Whether it's two bets or one depends on how many of the same stocks they hold, and at what weights.

Here's how I get an AI agent to measure that from the funds' own SEC filings.

Connect it first

In Claude, open Customize → Connectors → Discover, search for Equibles, click Connect to Claude and Authorize, then switch it on in a chat from + → Connectors. In ChatGPT: Plugins, search Equibles, Install plugin. In Claude Code, claude mcp add --transport http equibles https://mcp.equibles.com/mcp and then /mcp to sign in. The free plan covers 100 requests a day; other clients are in the setup docs.

1. Pull both portfolios in full

The prompt: "Using Equibles, list every holding of QQQ and XLK." The agent calls GetEtfHoldings with a maxResults large enough for each fund: 105 rows for QQQ and 79 for XLK, both from the funds' Form N-PORT reports for 30 June 2026, with full coverage. The top five of each:

Ask for the full list, not the top ten. Overlap lives in the tail too.

2. Match holdings on more than the ticker

Tickers alone don't line up. XLK's filing reports five holdings with a placeholder CUSIP of 000000000 and no ticker, Seagate and NXP among them. QQQ's lists Alphabet's second share class and Electronic Arts by CUSIP. Match on ticker and you'd miss Seagate and NXP, which both funds own.

So the instruction is: match on company name, then list every unmatched row so it can be checked by eye. That gives 36 companies held by both.

3. Measure the overlap

The method: for each common holding, take the smaller of its two weights, and add them up. That's the part of the two portfolios that is genuinely the same.

Common holdings:                       36
Overlap (sum of the smaller weight):   57.99%
QQQ weight in stocks XLK also holds:   58.21%
XLK weight in stocks QQQ also holds:   86.33%

Read the last two lines together. 86% of XLK sits in stocks QQQ also owns, while 42% of QQQ sits in stocks XLK doesn't own at all. Micron is the only common holding QQQ weights more heavily, 5.64% against 5.42%.

4. List what each one adds

"What does each fund hold that the other doesn't, by weight?"

• Only in QQQ: Alphabet 6.29% across two share classes, Amazon 4.02%, Tesla 3.30%, Meta 2.62%, Walmart 2.39%, Costco 1.80%, Netflix 1.30%.
• Only in XLK: IBM 1.47%, Oracle 1.39%, Amphenol 1.21%, Corning 1.11%, Arista Networks 0.98%, Salesforce 0.71%.

That follows from what each fund tracks. XLK holds the technology sector of the S&P 500, wherever the stocks are listed. QQQ holds the largest non-financial companies listed on Nasdaq, whatever their sector.

5. Check concentration and recent returns

"Show the profile for each." GetEtfProfile:

XLK's three largest holdings alone are 35.88% of the fund. Despite the overlap, the two have moved quite differently this year, which is the 42% of QQQ outside XLK at work.

The prompt I reuse

Using Equibles, compare ETFs <A> and <B>:
1. List every holding of both, with the report date.
2. Match on company name, then list unmatched rows for review.
3. Overlap = sum of the smaller weight per common holding; also give each
   fund's weight in the other's names.
4. List the largest holdings unique to each.
5. Add net assets, top-10 weight and YTD return.

What overlap can't tell you

• Today's portfolio. Holdings are as of 30 June 2026. Funds rebalance, and N-PORT reports appear with a lag.
• How they'll move together. Overlap by weight isn't correlation; two funds with little overlap can still fall together.
• Costs. Expense ratios aren't in this dataset, and the tool says so rather than guessing.

The holdings are also on each fund's page, like QQQ and XLK.

Nothing here is investment advice.