GSDAQ TOOLS
ETF overlap calculator
Calculate weighted overlap between two holdings lists in your browser. Your entered holdings are neither uploaded nor stored.
Use identifier,percent on each line, for example ALPHA,40, without a header. Up to 5,000 rows per list; each must total 100%.
The initial values are fictional Funds A and B, not real QQQ or SPY holdings. Their overlap is 25%.
Weighted overlap:
How is it calculated?
Current ETF holdings are not fetched automatically. Use complete lists with the same observation date and weight basis. For each shared holding, add the smaller of its two weights: Σ min(weight in A, weight in B). Identifiers are matched after uppercasing. Check that share classes, cash, derivatives and identifiers use comparable definitions. This tool is for comparable long-only holdings weights; it does not model short positions or leveraged exposure.
Do not rescale a top-holdings subset to 100%. A total check cannot establish completeness or authenticity. Overlap does not forecast returns, correlation or concentration across your entire portfolio.
Read the QQQ and SPY overlap guide