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WRDS (Wharton Research Data Services)

Learn how to access and use WRDS at NYU Libraries.

Linking Suite by WRDS

Linking Queries by WRDSallows users to easily download link tables between various heavily used databases on the WRDS platform. For example: 

  • Bond CRSP Link: Directly link fixed income data at the individual bond level to the equity data from the CRSP database. CUSIP PERMCO PERMNO   
  • TAQ CRSP Link: provides the link between TAQ SYMBOL and CRSP PERMNO 
  • IBES CRSP Link provides the historical matching of IBES TICKER with CRSP PERMNONCUSIP

For more information about linking in WRDS, also see Princeton-Matching Data in Financial Databases, Stanford-WRDS: Identifiers and Linking Files

Main Permanent Identifiers in WRDS Linking Suite

GVKEY: The Global Company Key or GVKEY is a unique six-digit number key assigned to each company (issue, currency, index) in the Capital IQ Compustat database. It is a company (issue, currency, index) identifier similar to a TICKER symbol. It represents the primary key for a company that is an index constituent.

PERMNO: CRSP permanent number. The PERMNO is a unique permanent identifier for a security. Companies may have several stocks at one time so each PERMCO may be associated with more than one PERMCO. In short, no, a PERMNO cannot change. It stays constant through changes of TICKER, CUSIP, company / security name, and other changes.

However, a security may be delisted and new ones created. For example, PERMNO 16707  is used for the  MANVILLE CORP (date range: 19280229-19881130) before a reorganization in late 1988.  The new PERMNO is 90100 for MANVILLE CORP  (date range: 19881130-20010228), which the CRSP database also describes as JOHNS MANVILLE CORP NEW.

PERMCOCRSP permanent company number. PERMCO is a unique permanent identifier assigned by CRSP to a company with issues on a CRSP file. This number is permanent regardless of name changes. If the value in this field is less than 20,000, CRSP has used the Nasdaq-assigned Company Number, for when the company had an issue trading on The Nasdaq Stock Market(SM). A value over 20,000 indicates that the number was assigned by CRSP.

CUSIP: derives from Committee on Uniform Security Identification Procedures, is a nine-digit numeric (e.g. 037833100 for Apple) or nine-character alphanumeric (e.g. 38259P508 for Google) code that identifies a North American financial security for the purposes of facilitating clearing and settlement of trades. 

The CUSIP identifier can have 6, 8, or 9 digits. The first 6 digits refer to the company, the next 2 refer to the security, and the 9th is a check-digit that has no inherent meaning. CRSP uses 8-digit CUSIPs. 

CUSIP Converter: This tool enables you to convert either 8 or 9 digit CUSIPs into 6, 8, or 9 digits.

NCUSIP:  The 8 character historical CUSIP identifier for a security (from CRSP). Note that the final value of NCUSIP is the current value of CUSIP.

TICKER: A unique IBES identifier assigned to each security that is consistent throughout IBES History 

ISIN: An International Securities Identification Number (ISIN) is a 12-digit alphanumeric code that uniquely identifies a specific security. For US companies ISIN is made up of the CUSIP with a few extra characters.

ISIN = 2 character country code + 9 character CUSIP + check digit, e.g., Tesla: ISIN: US88160R1014; CUSIP: 88160R101

CIK: Central Index Key: unique registrant identifying ID from US SEC.

SYMBOL: Stock Symbol (symbol) in TAQ

Video Tutorial: WRDS Linking Procedures

The video (21'44") about the basics to linking databases.