CRSP_CCM_LINKUSED - CRSP-Centric Link Used History

Itm_name Type Description
PERMNO* integer, primary key (1) CRSP PERMNO used as basis for this history
ULINKID integer Unique ID per link associated with PERMNO. This is used to join with range data in the LINKRANGE table that describes the data ranges applied from used GVKEYs.
UGVKEY integer Compustat GVKEY
UIID char(3) Compustat IID
ULINKDT integer (date), primary key (2) First effective calendar date of link record range
ULINKENDDT integer (date) Last effective calendar date of link record range
UPERMNO integer Linked CRSP PERMNO, 0 if no CRSP security link exists
UPERMCO integer Linked CRSP PERMCO, 0 if no CRSP company link exists
ULINKPRIM char(3) Primary issue marker for the link. Based on Compustat Primary/Joiner flag (PRIMISS), indicating whether this link is to Compustat’s marked primary security during this range.
  • P = Primary, identified by Compustat in monthly security data.
  • J = Joiner secondary issue of a company, identified by Compustat in monthly security data.
  • C = Primary, assigned by CRSP to resolve ranges of overlapping or missing primary markers from Compustat in order to produce one primary security throughout the company history.
  • N = Secondary, assigned by CRSP to override Compustat. Compustat allows a US and Canadian security to both be marked as Primary at the same time. For Purposes of the link, CRSP allows only one primary at a time and marks the others as N.
ULINKTYPE char(3) Link type code. Each link is given a code describing the connection between the CRSP and Compustat data. Values are:
  • LC – Link research complete. Standard connection between databases.
  • LU – Unresearched link to issue by CUSIP. (LU ignores LD.)
  • LX – Link to a security that trades on foreign exchange not included in CRSP data.
  • LD – Duplicate Link to a security. Another GVKEY/IID is a better link to that CRSP record. (2 GVKEYs - duplicate record.)
  • LN – Primary link exists but Compustat does not have prices.
  • LS – Link valid for this security only. Other CRSP PERMNOs with the same PERMCO will link to other GVKEYs. (Happens frequently for ETFs.)
  • NR – No link available, confirmed by research
  • NU – No link available, not yet confirmed
USEDFLAG integer 1 = this link is applicable to the selected PERMNO and used to identify ranges of Compustat data from a GVKEY used to build a composite GVKEY record corresponding to the PERMNO.
-1 = this link is informational, indirectly related to the PERMNO, but not used.

* - The PERMNO is the CRSP security identifier used as the basis for a composite Compustat record and serves as the primary identifier for the composite record. In CRSPAccess programming this field is not present in the structure but inherited from the master structure for the company. The APERMNO or PPERMNO key types store the PERMNO in the CCM structure CCMID field and marks the CCMIDTYPE as 3. In standalone usage the PERMNO field is included.