Native Link usage provides access to Compustat records, regardless of whether or not securities are in the CRSP universe. All Compustat data including index data, Canadian records, and off-exchange ranges that cannot be directly linked to CRSP Data are accessed using GVKEY, GVKEY.IID, and GVKEYX. The native link reads Compustat data as organized and identified by Compustat identifiers and can choose CRSP data appropriate to those records. Decisions on handling overlaps or soft links are left to the user.
Mnemonic
Field Name
Format
LINKDT
linkdt is a calendar date in YYYYMMDD format marking the first effective date of the current link. It is derived from the first or last date of a CRSP exchange listing, the date of a CRSP name change corresponding to the beginning or end of the link the rows of available Compustat data, or the date of a Compustat description change corresponding to the beginning or end of the link.
If a linkdt is derived from a last date, it will actually be the day after the last date. Since CRSP keeps link records for the entire Compustat history, if the Compustat history ends after the CRSP history, the linkdt of a row marking a no-link period can start the day after the CRSP delist date.
integer
LINKENDDT
Last effective date of the link record. If the name represents current link information, the LINKENDDT is set to 99999999
integer
LPERMNO
CRSP PERMNO link during link period. It is set to zero if there is no CRSP link during the range.
integer
LPERMCO
CRSP PERMCO link during link period. It is set to zero if there is no CRSP link during the range.
integer
LIID
Security identifier
character
LNKTYPE
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
LX – Link to a security that trades on another exchange system not included in CRSP data.
LD – Duplicate link to a security. Another GVKEY/IID is a better link to that CRSP record.
LS – Link valid for this security only. Other CRSP PERMNOs with the same PERMCO will link to other GVKEYs.
LN – Primary link exists but Compustat does not have prices.
NR – No link available, confirmed by research
NU – No link available, not yet confirmed
character
LINKPRIM
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.
character
LINKUSED Defined Structure
LINKUSED includes all of the fields in the link sturcture plus UGVKEY and USEDFLAG. Its number of rows exceeds that of the link structure because it has all link records of all GVKEYs with a match to a PERMNO, even those not used. USEDFLAG = 1 in LINKUSED is a subset of the available link records. It is loaded each time data are accessed in CRSP-Centric mode, such as for ts_print, TsQuery, or when C functions are run. The function builds a composite Compustat record from one or more Compustat GVKEYs and IIDs linked to a CRSP PERMNO. LINKUSED data are accessed using the composite PERMNO, APERMNO, or the Primary PERMNO, PPERMNO.
Mnemonic
Field Name
Internal Storage
ULINKDT
ulinkdt is a calendar date in YYYYMMDD format marking the first effective date of the current link. It is derived from the first or last date of a CRSP exchange listing, the date of a CRSP name change corresponding to the beginning or end of the link the rows of available Compustat data, or the date of a Compustat description change corresponding to the beginning or end of the link.
integer
ULINKENDDT
Last effective date of the link record. If the name represents current link information, the ULINKENDDT is set to 99999999
integer
ULINKID
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.
integer
UGVKEY
GVKEY used in the link
integer
UPERMNO
CRSP PERMNO link during link period. It is set to zero if there is no CRSP link during the range.
integer
UPERMCO
CRSP PERMCO link during link period. It is set to zero if there is no CRSP link during the range.
integer
UIID
Used Security ID
character
USEDFLAG
Flag marking whether link is used in building composite record
character
ULINKPRIM
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.
character
ULINKTYPE
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
LX – Link to a security that trades on another exchange system not included in CRSP data.
LD – Duplicate Link to a security. Another GVKEY/IID is a better link to that CRSP record.
LS – Link valid for this security only. Other CRSP PERMNOs with the same PERMCO will link to other GVKEYs.
LN – Primary link exists but Compustat does not have prices.
NR – No link available, confirmed by research
NU – No link available, not yet confirmed
character
LINKRNG Defined Structure
CRSP generates a range table with information on the fiscal periods associated with each used link for each time series calendar frequency and keyset. This shows ranges in each of the fiscal and calendar calendars available in the CCM. This range table shows the ranges from the GVKEY for each type of time series data used to build the composite record for the PERMNO selected.
Mnemonic
Field Name
Format
RLINKID
Linkused row identifier
integer
RKEYSET
Keyset applicable to range
integer
RCALID
Calendar applicable to range
integer
RBEGIND
Beginning time series range of link
integer
RENDIND
Ending time series range of link
integer
RPREVIND
Time series range immediately prededing the link
integer
RBEGDT
Beginning calendar range of link
integer
RENDDT
Ending calendar range of link
integer
RPREVDT
Ending calendar range preceding the link
int(4)
RFISCAL_DATA_FLG
Type of time series, C-calendar or F-fiscal.
char(8)
CRSP-Centric Link Usage
Accessing Compustat data through ts-print and TsQuery is done through the CRSP-centric mode, meaning that the primary access key in this mode is CRSP PERMNO or PERMCO rather than GVKEY, as used in the Native Access mode. The CRSP identifiers are the access keys while the Compustat identifiers become attributes.
In CRSP-Centric mode a composite record is built using the CRSP Link reading one or more GVKEYs. All GVKEYS with some presence of the PERMNO in the link are accessed. A used-link history is built from these link records by identifying those that cover the ranges of Compustat data needed to link to the CRSP identifier. The USEDFLAG for time series items that are stored on a fiscal period basis, the link ranges are translated to a fiscal range. This translation simplifies the selection of fundamental data that are applicable to the range and allows for the creation of a composite Compustat record from the applicable ranges that correspond to a CRSP security.
Records in CRSP-Centric form are identical in layout to the native records, but use CRSP PERMNO as the effective key. The Compustat component identifiers – GVKEY, IID, and PRIMISS are available in a Link Used table in the CRSP records.
Using the CRSP-Centric view simplifies access when viewing Compustat data through CRSP. One drawback, however, is that only data considered a primary link to CRSP, applied using CRSP link rules, are available.
Accessing two separate GVKEYs from the Link table, see that both share a single PERMNO.
GVKEY = 011947
Link History
LINKDT
LINKENDDT
LPERMNO
LPERMCO
LIID
LINKTYPE
LINKPRIM
19820701
19860304
0
0
00X
NR
C
19860305
19890228
10083
8026
01
LU
P
GVKEY = 015495
Link History
LINKDT
LINKENDDT
LPERMNO
LPERMCO
LIID
LINKTYPE
LINKPRIM
19880101
19890227
0
0
00X
NU
C
19890228
19930909
10083
8026
01
LC
C
19930910
19990304
0
0
01
NR
C
Using CRSP-Centric access in the USEDLINK table, access the composite history using the Primary PERMNO (LINKPRIM=P)
Subscription Information
LINK Defined Structure
Native Link usage provides access to Compustat records, regardless of whether or not securities are in the CRSP universe. All Compustat data including index data, Canadian records, and off-exchange ranges that cannot be directly linked to CRSP Data are accessed using GVKEY, GVKEY.IID, and GVKEYX. The native link reads Compustat data as organized and identified by Compustat identifiers and can choose CRSP data appropriate to those records. Decisions on handling overlaps or soft links are left to the user.
linkdt is a calendar date in YYYYMMDD format marking the first effective date of the current link. It is derived from the first or last date of a CRSP exchange listing, the date of a CRSP name change corresponding to the beginning or end of the link the rows of available Compustat data, or the date of a Compustat description change corresponding to the beginning or end of the link.
If a linkdt is derived from a last date, it will actually be the day after the last date. Since CRSP keeps link records for the entire Compustat history, if the Compustat history ends after the CRSP history, the linkdt of a row marking a no-link period can start the day after the CRSP delist date.
LINKUSED Defined Structure
LINKUSED includes all of the fields in the link sturcture plus UGVKEY and USEDFLAG. Its number of rows exceeds that of the link structure because it has all link records of all GVKEYs with a match to a PERMNO, even those not used. USEDFLAG = 1 in LINKUSED is a subset of the available link records. It is loaded each time data are accessed in CRSP-Centric mode, such as for ts_print, TsQuery, or when C functions are run. The function builds a composite Compustat record from one or more Compustat GVKEYs and IIDs linked to a CRSP PERMNO. LINKUSED data are accessed using the composite PERMNO, APERMNO, or the Primary PERMNO, PPERMNO.
LINKRNG Defined Structure
CRSP generates a range table with information on the fiscal periods associated with each used link for each time series calendar frequency and keyset. This shows ranges in each of the fiscal and calendar calendars available in the CCM. This range table shows the ranges from the GVKEY for each type of time series data used to build the composite record for the PERMNO selected.
CRSP-Centric Link Usage
Accessing Compustat data through ts-print and TsQuery is done through the CRSP-centric mode, meaning that the primary access key in this mode is CRSP PERMNO or PERMCO rather than GVKEY, as used in the Native Access mode. The CRSP identifiers are the access keys while the Compustat identifiers become attributes.
In CRSP-Centric mode a composite record is built using the CRSP Link reading one or more GVKEYs. All GVKEYS with some presence of the PERMNO in the link are accessed. A used-link history is built from these link records by identifying those that cover the ranges of Compustat data needed to link to the CRSP identifier. The USEDFLAG for time series items that are stored on a fiscal period basis, the link ranges are translated to a fiscal range. This translation simplifies the selection of fundamental data that are applicable to the range and allows for the creation of a composite Compustat record from the applicable ranges that correspond to a CRSP security.
Records in CRSP-Centric form are identical in layout to the native records, but use CRSP PERMNO as the effective key. The Compustat component identifiers – GVKEY, IID, and PRIMISS are available in a Link Used table in the CRSP records.
Using the CRSP-Centric view simplifies access when viewing Compustat data through CRSP. One drawback, however, is that only data considered a primary link to CRSP, applied using CRSP link rules, are available.
Accessing two separate GVKEYs from the Link table, see that both share a single PERMNO.
GVKEY = 011947
GVKEY = 015495
Using CRSP-Centric access in the USEDLINK table, access the composite history using the Primary PERMNO (LINKPRIM=P)
PERMNO = 10083