PERMNO® & PERMCO®

Permanent Identifiers. Proven Precision.

PERMNO® & PERMCO® are the foundation of CRSP Data’s infrastructure, providing permanent, unchanging identifiers that track securities across their full lifecycle. Unlike tickers or CUSIPs, these identifiers remain consistent through mergers, name changes, and restructurings. The result is seamless historical alignment, reliable back-testing, and lasting data integrity trusted by institutions and researchers for decades.

Used in over 

0 +

published studies

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Tickers change. PERMNO doesn’t.

Our identifiers persist across a security’s entire lifecycle – from IPO through restructuring – providing the stable foundation that financial data demands.

Mergers. Acquisitions.

PERMNO follows securities over the course of time and across corporate actions, ensuring seamless datasets that account for structural changes.

Historical analysis requires consistency.

PERMNO provides a unified reference key, allowing researchers to compare decades of market activity without gaps.

Back-tests are only as good as their data.

With stable identifiers and accurate linkages, PERMNO lets analysts run simulations with confidence.

CRSP Data runs on PERMNO.

As the foundation of CRSP’s securities database, PERMNO ensures that every dataset we provide is accurate, replicable, and aligned with academic and institutional standards.

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Get access to the data powering groundbreaking research and policy.

Connect With Us!

Get access to the data powering groundbreaking research and policy.

Explore Studies Backed by CRSP Research Data

CRSP Data has powered thousands of peer-reviewed publications, financial models, and regulatory studies with nearly a century of data. Our identifiers ensure those insights rest on a stable, consistent foundation.

CRSP Market Indexes (CRSPMI) announces the market cap breakpoints and effective ranking dates for its September 2025 quarterly index rebalancing. [...]
Using CRSP Market Indexes Methodology, CRSP Count™ tracks changes in the number of securities by market cap segments - Mega, Mid, Small and Micro - through time. [...]
Why do some mid- and small-cap ETFs outperform others? A recent article from ETF.com highlights how benchmark index construction and methodology—especially market cap definitions—can significantly impact ETF performance. [...]
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