Building an Auditable U.S. Equity Universe from Nasdaq Listings

Summary

The document describes a reproducible process for building a U.S. equity symbol master from Nasdaq Trader’s listed-symbol directory. It parses the pipe-delimited file, checks for expected fields, removes rows marked as test issues, and saves the cleaned records. It also preserves the downloaded source snapshot, records the file’s own creation time, and calculates hashes for both the input and output files so later users can verify which data version they used.

The document reports one run’s input and output row counts and hashes as evidence of execution, while warning that these values describe only that snapshot and will change as the directory is updated. The method establishes symbol-list provenance, not tradability or investment suitability: excluding test issues does not guarantee broker access, and financial status is not a trading signal. The directory is neither real-time market data nor a source of complete company fundamentals. The procedure is a data-engineering starting point and calls for retaining dated snapshots and processing logs in ongoing use.

Key ideas

• Use an official symbol directory as a source for constructing an equity universe.
• Validate expected columns before processing the listing file.
• Filter test issues while retaining the original downloaded snapshot.
• Record the source file’s creation time and hashes to support later verification.
• A non-test listing does not establish broker tradability or provide real-time or fundamental data.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.