aggregate-holdings-across-multiple-funds

name	Aggregate-Holdings-Across-Multiple-Funds
description	Search multiple funds' holdings data for a specific security (by CUSIP) and aggregate the total share values held by each fund manager. Use this to rank fund managers by their investment in a particular security.

Steps

1. Prepare the CUSIP to search

   • Confirm you have the correct CUSIP for the target security
   • Document the security name for reference

2. Iterate through all available funds

   • Determine which fund data files exist in the data folder
   • For each fund, load its holdings data for the target quarter

3. Search for the CUSIP in each fund's holdings

   • Filter holdings to rows matching the target CUSIP
   • If found, extract the market value and fund manager name
   • If not found, record that this fund does not hold the security

4. Aggregate results

   • Create a summary table with fund manager name and total market value invested in the security
   • Sort by market value in descending order

5. Select top results

   • Rank funds by market value invested (largest first)
   • Extract the top 3 fund manager names

6. Validate the results

   • Confirm that the top funds are known large investors (e.g., Berkshire Hathaway, Renaissance)
   • Spot-check a few holdings to verify CUSIP matches are correct
   • Flag if results seem unusual or incomplete