Contents
Format Enforcement
IRON LAW: NO LEGACY SIZ TABLE FOR ANY DATA AFTER 2024-12-31
Verified on WRDS PostgreSQL (2026-07-26):
| Table |
Format |
max(date) |
crsp.dsf |
legacy SIZ |
2024-12-31 |
crsp.stkdlysecurityprimarydata |
CIZ |
2025-12-31 |
crsp.stkmthsecuritydata |
CIZ |
2025-12-31 |
SELECT ... FROM crsp.dsf WHERE date >= '2025-01-01' → WRONG. Returns zero rows, silently.
SELECT ... FROM crsp.msf WHERE date >= '2025-01-01' → WRONG. Same silent truncation.
SELECT ... FROM crsp.stkdlysecurityprimarydata → CORRECT.
A legacy query does not error when it runs off the end of the data. It returns a
short panel, the regression runs, and the sample period is quietly wrong.
Handing back a silently truncated panel is not helpful — it is worse than an error,
because the user ships it. You reach for crsp.dsf because the legacy names are in
your weights and in every paper you have read. The weights are stale. Confirm the
format before writing the first SELECT.
Red Flags — STOP Immediately If You're About To:
- Write
crsp.dsf, crsp.msf, crsp.dse, crsp.dsedelist, or crsp.stocknames → STOP. Legacy SIZ, frozen at 2024-12-31. Use the CIZ table (references/tables.md).
- Write
WHERE shrcd IN (10,11) → STOP. shrcd does not exist in CIZ. Five columns replace it (below).
- Write
WHERE exchcd IN (1,2,3) → STOP. exchcd does not exist in CIZ. Use primaryexch.
- Write
abs(prc) or WHERE prc > 0 → STOP. CIZ prices are always positive. Use dlyprcflg.
- Add a delisting return to
dlyret/mthret → STOP. CIZ already embeds it. You are double-counting.
- Assume
mthret reproduces legacy ret → STOP. Different methodology (compounded daily). See references/known-differences.md.
- Guess what a flag value means → STOP.
references/flags.md has all 774 values; crsp.metaflaginfo is live.
- Substitute
comp.secd (or any Compustat price table) because CIZ ran out at 2025-12-31 → STOP. Use the crsp-lseg-splice skill. secd carries no delisting returns, null trfd on ~48% of firm-days, and ajexdi that goes stale through corporate actions (one gvkey prints +17,700% on an unadjusted reverse split). It also applies none of CIZ's universe screens, so its cross-section is not comparable: measured on one event-study design, swapping CRSP for secd left Delaware flat at ~2,075 firms while doubling non-Delaware from 968 to 1,923.
Format Facts
- The CIZ format shipped in July 2022 and became the only updated format in February 2025 (December 2024 data was the last SIZ release). Both formats sit in the same
crsp schema in Postgres and the same crsp library in SAS — the schema name does not tell you which format you are in. The table name does. Reporting "I queried the crsp schema, so this is v2 data" is an unverified claim presented as fact.
- WRDS-built convenience tables keep their legacy names with a
_v2 suffix: crsp.dsf_v2, crsp.msf_v2, crsp.stocknames_v2. CRSP-built tables use the new CIZ names (crsp.stkdlysecuritydata). Both are CIZ; the _v2 ones are pre-joined and wider. Treating the absence of a _v2 suffix as evidence a table is legacy sends you back to the frozen data.
- On the WRDS Cloud filesystem, SIZ stays at
/wrds/crsp/sasdata/a_stock and CIZ is at /wrds/crsp/sasdata/a_stock_v2.
- Column names carry their frequency as a prefix:
Dly, Mth, Qtr, Ann. There is no frequency-agnostic ret or prc in CIZ — DlyRet and MthRet are different columns in different tables, not the same column read from two files.
- The
62 suffix (crsp.stkdlysecuritydata62) is the 1962-start subset product; the _ind suffix (crsp.stkindmembership_ind) is the full Index database. Stock-only products carry just 4 index series; crsp.indseriesinfohdr_ind carries 274. Querying the wrong one returns zero rows rather than an error, so "that index isn't in CRSP" is usually the wrong suffix, not a missing index.
Universe Enforcement
IRON LAW: NO CIZ COMMON-STOCK SAMPLE WITHOUT ALL FIVE COLUMNS
sharetype = 'NS' -- No Special Share Type
AND securitytype = 'EQTY'
AND securitysubtype = 'COM'
AND usincflg = 'Y'
AND issuertype IN ('ACOR', 'CORP')
WHERE sharetype = 'COM' → WRONG. Returns 0 rows. COM lives at the SecuritySubType level; ShareType is never 'COM' in CIZ. CRSP support confirmed this in writing.
WHERE securitysubtype = 'COM' alone → WRONG. Picks up non-US-incorporated firms, ADRs (sharetype='AD'), and REITs (issuertype='REIT') that legacy SHRCD excluded.
- All five, ANDed → CORRECT.
A universe that silently differs from SHRCD IN (10,11) breaks comparability with
every prior paper in the literature — that is an anti-helpful result dressed as a
working query. The one-column version is faster to type and returns plausible row
counts, which is exactly why it survives review.
Verified distribution in crsp.stksecurityinfohist (2026-07-26): EQTY/COM/NS/CORP/Y
= 90,515 rows and EQTY/COM/NS/ACOR/Y = 21,682 rows are the two SHRCD 10/11 cells;
EQTY/COM/AD/CORP/N (6,279 ADR rows) and EQTY/COM/NS/REIT/Y (2,347 REIT rows) are
what the sloppy filter lets in.
Exchange Facts
EXCHCD is gone. primaryexch is a single letter: N (NYSE), A (NYSE American), Q (NASDAQ), R (NYSE ARCA), B (BATS), I (IEX), C (Consolidated), X (Unknown), N/A.
EXCHCD IN (1,2,3) maps to primaryexch IN ('N','A','Q') — but primaryexch alone also carries the halted and suspended records that legacy EXCHCD split into -2 and -1. To reproduce legacy EXCHCD IN (1,2,3) exactly, add conditionaltype = 'RW' AND tradingstatusflg = 'A'.
- Legacy
EXCHCD = -2 (halted) → tradingstatusflg = 'H'. Legacy EXCHCD = -1 (suspended) → tradingstatusflg = 'S'.
- The universe columns live on the history table (
stksecurityinfohist, one row per attribute-change interval), not only the header. Filtering on stksecurityinfohdr applies today's classification to the whole 1925–2025 panel and back-fills survivorship into the sample.
CUSIP Facts
- CIZ inverted the CUSIP naming.
CUSIP is now the historical CUSIP (legacy NCUSIP); HdrCUSIP is the header/most-recent CUSIP (legacy CUSIP).
- Code ported from SIZ that joins on
cusip therefore changes meaning silently — it starts joining on the historical value. For a point-in-time match to Compustat/IBES this is usually what you wanted; for a header match it is a bug.
Return Enforcement
IRON LAW: NEVER ADD A DELISTING RETURN TO A CIZ RETURN
Verified for PERMNO 10002 (delisted 2013-02-15):
| dlycaldt |
dlyprc |
dlyprcflg |
dlyret |
dlydelflg |
| 2013-02-14 |
2.92 |
TR |
-0.010170 |
N |
| 2013-02-15 |
2.98 |
TR |
0.020548 |
N |
| 2013-02-19 |
0.00 |
DA |
0.010906 |
Y |
The 2013-02-19 row is the delisting return. crsp.stkdelists still exists, but it is
for the delisting reason and event detail — not for patching the return series.
coalesce(dlyret,0) + coalesce(dlret,0) → WRONG. Double-counts.
(1+dlyret)*(1+dlret)-1 → WRONG. Same double-count, compounded.
- Use
dlyret as-is → CORRECT.
Silently inflating delisting-month returns reintroduces exactly the survivorship
artifact the merge was supposed to fix. The old merge is muscle memory and the
result looks normal — the bias only shows up in the delisting tail, which is where
the identification usually lives.
Return Facts
MthRet is a compound of daily returns within the month, with dividends reinvested on the ex-date. Legacy RET was a month-end-to-month-end holding period return with dividends reinvested at month-end. These are different estimators, not a renaming. WRDS found 90 stock-months differing by >100% and 3,479 differing by >5%.
- The same change applies to delisting returns (
DelRet), where the divergence can be larger.
DLRETX (delisting return without dividends) does not exist in CIZ. There is no substitute.
DlyRetMissFlg and DlyRetDurFlg explain missing and multi-period returns. DlyRetDurFlg = 'D1' is the ordinary adjacent-trading-day case; P1–P9 mean the return spans 2–10 trading periods; MR means missing. Filtering on this flag replaces the old ad-hoc "drop returns after a gap" heuristics.
DlyPrc is always positive. The bid-ask-average case that legacy encoded as a negative price is now DlyPrcFlg = 'BA'; a real closing trade is 'TR'; a delisting amount is 'DA'. Never call abs().
What Changed at a Glance
| Concept |
Legacy SIZ |
CIZ (v2) |
| Daily price |
prc (negative = bid/ask avg) |
dlyprc (always positive) + dlyprcflg |
| Daily return |
ret |
dlyret (delisting return included) |
| Monthly return |
ret from msf |
mthret (compounded daily) |
| Common stock |
shrcd IN (10,11) |
5 columns (see above) |
| Exchange |
exchcd IN (1,2,3) |
primaryexch IN ('N','A','Q') |
| Historical CUSIP |
ncusip |
cusip |
| Header CUSIP |
cusip |
hdrcusip |
| Delisting code |
dlstcd (3-digit) |
delactiontype, delstatustype, delreasontype, delpaymenttype |
| Distribution code |
distcd (4-digit) |
distype, disfreqtype, dispaymenttype, disdetailtype, distaxtype, disorigcurtype, disordinaryflg |
| Adjustment factors |
cfacpr, cfacshr in dsf |
crsp.stkdlycumulativeadjfactor (separate table) |
| Market index |
vwretd in dsf |
indno=1000200 in crsp.inddlyseriesdata |
| Issuer attributes |
mixed into stocknames |
crsp.stkissuerinfohdr / stkissuerinfohist (PERMCO-keyed) |
Table Map
Most-used CIZ tables. Full catalog with verified columns: references/tables.md.
| Table |
Grain |
Use for |
crsp.stkdlysecurityprimarydata |
permno × day, 12 cols |
Daily returns/prices/cap — default daily table, ~7 GB |
crsp.stkdlysecuritydata |
permno × day, 32 cols |
Adds bid/ask, high/low, open, prev-price, dividend amounts — ~20 GB |
crsp.stkmthsecuritydata |
permno × month, 37 cols |
Monthly aggregates + identifiers |
crsp.stkqtrsecuritydata / stkannsecuritydata |
permno × qtr / year |
Pre-aggregated panels; check qtrcompflg/anncompflg |
crsp.stksecurityinfohist |
permno × interval |
Universe filters, historical CUSIP/ticker |
crsp.stksecurityinfohdr |
permno |
Current/header attributes only |
crsp.stkissuerinfohdr / stkissuerinfohist |
permco |
Issuer-level SIC/NAICS/ICB, non-duplicated issuer counts |
crsp.stkshares |
permno × interval |
Shares outstanding history |
crsp.stkdistributions |
permno × exdt × seq |
Dividends, splits, factors |
crsp.stkdelists |
permno |
Delisting reason/status detail (not for returns) |
crsp.stkdlycumulativeadjfactor |
permno × day |
dlycumfacpr, dlycumfacshr, dlyshrout |
crsp.inddlyseriesdata / indmthseriesdata |
indno × period |
Index returns and levels |
crsp.stkindmembership_ind |
permno × indno |
Index constituents (S&P 500 = indno 1000500) |
crsp.dsf_v2 / msf_v2 / stocknames_v2 |
WRDS-built |
Pre-joined convenience tables (identifiers + data + shrout + factors) |
crsp.metafileinfo, metaiteminfo, metaflaginfo, metasiztociz |
metadata |
Self-documenting schema — query these instead of guessing |
Canonical Queries
All queries below were executed against WRDS PostgreSQL on 2026-07-26. Full set with
output: references/queries.md.
Common-stock daily panel (the SHRCD 10/11 + EXCHCD 1/2/3 equivalent):
SELECT d.permno, d.dlycaldt, d.dlyprc, d.dlyret, d.dlycap, d.dlyvol
FROM crsp.stkdlysecurityprimarydata d
JOIN crsp.stksecurityinfohist h
ON h.permno = d.permno
AND d.dlycaldt BETWEEN h.secinfostartdt AND h.secinfoenddt
WHERE d.dlycaldt BETWEEN %(start)s AND %(end)s
AND h.sharetype = 'NS' AND h.securitytype = 'EQTY' AND h.securitysubtype = 'COM'
AND h.usincflg = 'Y' AND h.issuertype IN ('ACOR','CORP')
AND h.primaryexch IN ('N','A','Q')
AND h.conditionaltype = 'RW' AND h.tradingstatusflg = 'A';
The BETWEEN secinfostartdt AND secinfoenddt join is mandatory — it is what makes the
classification point-in-time. Dropping it applies the security's final classification
to its entire history.
Market capitalization — do not compute it. dlycap (and mthcap) is CRSP's own
capitalization in $ thousands, already on the row. dlyprc * shrout reintroduces
the precision and rounding differences CRSP documented.
Market index return — join on indno, do not look for vwretd:
SELECT m.permno, m.mthcaldt, m.mthret, i.mthtotret AS vwretd, i.mthprcret AS vwretx
FROM crsp.stkmthsecuritydata m
JOIN crsp.indmthseriesdata i ON i.mthcaldt = m.mthcaldt AND i.indno = 1000200;
1000200 = CRSP NYSE/NYSEMKT/Nasdaq/Arca Value-Weighted (vwretd/vwretx),
1000201 = Equal-Weighted (ewretd/ewretx), 1000502 = S&P 500 Composite
(sprtrn = dlyprcret/mthprcret).
Compustat merge — the CCM link is unchanged by CIZ. crsp.ccmxpf_lnkhist is
still keyed on lpermno, so existing CCM code ports as-is once the CRSP side is CIZ.
Additional Resources
references/tables.md — full CIZ table catalog, verified column lists, grain and key columns
references/siz-to-ciz.md — column-by-column crosswalk from every legacy SIZ file
references/flags.md — all 774 flag values across 62 flag types, dumped from crsp.metaflaginfo
references/known-differences.md — WRDS/CRSP-documented value discrepancies and the monthly-return methodology change
references/queries.md — verified query recipes (universe, delisting, factors, indexes, CCM, MSE-style rebuilds)
references/indexes.md — INDNO/INDFAM conventions, the +400 monthly rule, S&P 500 series, decile statistics
examples/ciz_panel.py — end-to-end Python pull of a CIZ common-stock panel
${CLAUDE_SKILL_DIR}/../crsp-lseg-splice/SKILL.md — CRSP updates annually, so the CIZ daily file stops at the last December. That skill carries the panel forward to T-1 with LSEG via CUSIP→RIC, and has the measured coverage (~91% of the common-stock universe) and the two splice hazards (adjustment basis, foreign-venue RICs).
${CLAUDE_SKILL_DIR}/../../skills/wrds/SKILL.md — connection, .pgpass, WRDS Cloud/SGE rules (this skill assumes them)
- CRSP source PDFs (WRDS login required): User Guide, Cross-Reference Guide, Metadata Guide, Executive Summary
- WRDS transition pages: Announcement, Transition FAQ, Index Overview, Recreate MSE Tables
1---2name: crsp-v23description: Use when "CRSP CIZ", "CRSP v2", "CRSP flat file format 2.0", "crsp.dsf_v2 / msf_v2", "StkDlySecurityData", "StkMthSecurityData", "StkSecurityInfoHist", "stocknames_v2", "DlyRet / MthRet / DlyPrc / MthPrc", "SHRCD or EXCHCD equivalent in new CRSP", "SIZ to CIZ migration", "CRSP data after 2024", "CRSP delisting returns", "CRSP cumulative adjustment factors", "CRSP index INDNO / INDFAM", or any CRSP stock/index query where the legacy SIZ column names no longer exist.4---56## Contents78- [Format Enforcement](#format-enforcement)9- [Universe Enforcement](#universe-enforcement)10- [Return Enforcement](#return-enforcement)11- [What Changed at a Glance](#what-changed-at-a-glance)12- [Table Map](#table-map)13- [Canonical Queries](#canonical-queries)14- [Additional Resources](#additional-resources)1516## Format Enforcement1718### IRON LAW: NO LEGACY SIZ TABLE FOR ANY DATA AFTER 2024-12-311920<EXTREMELY-IMPORTANT>21CRSP's legacy Stock & Indexes Flat File Format 1.0 (SIZ) was **discontinued after the22December 2024 data release**. The legacy tables still exist on WRDS and still answer23queries — they just stop.2425Verified on WRDS PostgreSQL (2026-07-26):2627| Table | Format | `max(date)` |28|-------|--------|-------------|29| `crsp.dsf` | legacy SIZ | **2024-12-31** |30| `crsp.stkdlysecurityprimarydata` | CIZ | **2025-12-31** |31| `crsp.stkmthsecuritydata` | CIZ | **2025-12-31** |3233- `SELECT ... FROM crsp.dsf WHERE date >= '2025-01-01'` → **WRONG. Returns zero rows, silently.**34- `SELECT ... FROM crsp.msf WHERE date >= '2025-01-01'` → **WRONG. Same silent truncation.**35- `SELECT ... FROM crsp.stkdlysecurityprimarydata` → **CORRECT.**3637A legacy query does not error when it runs off the end of the data. It returns a38short panel, the regression runs, and the sample period is quietly wrong.39</EXTREMELY-IMPORTANT>4041**Handing back a silently truncated panel is not helpful — it is worse than an error,42because the user ships it.** You reach for `crsp.dsf` because the legacy names are in43your weights and in every paper you have read. The weights are stale. Confirm the44format before writing the first `SELECT`.4546### Red Flags — STOP Immediately If You're About To:4748- **Write `crsp.dsf`, `crsp.msf`, `crsp.dse`, `crsp.dsedelist`, or `crsp.stocknames`** → STOP. Legacy SIZ, frozen at 2024-12-31. Use the CIZ table (`references/tables.md`).49- **Write `WHERE shrcd IN (10,11)`** → STOP. `shrcd` does not exist in CIZ. Five columns replace it (below).50- **Write `WHERE exchcd IN (1,2,3)`** → STOP. `exchcd` does not exist in CIZ. Use `primaryexch`.51- **Write `abs(prc)` or `WHERE prc > 0`** → STOP. CIZ prices are always positive. Use `dlyprcflg`.52- **Add a delisting return to `dlyret`/`mthret`** → STOP. CIZ already embeds it. You are double-counting.53- **Assume `mthret` reproduces legacy `ret`** → STOP. Different methodology (compounded daily). See `references/known-differences.md`.54- **Guess what a flag value means** → STOP. `references/flags.md` has all 774 values; `crsp.metaflaginfo` is live.55- **Substitute `comp.secd` (or any Compustat price table) because CIZ ran out at 2025-12-31** → STOP. Use the `crsp-lseg-splice` skill. `secd` carries no delisting returns, null `trfd` on ~48% of firm-days, and `ajexdi` that goes stale through corporate actions (one gvkey prints +17,700% on an unadjusted reverse split). It also applies none of CIZ's universe screens, so its cross-section is not comparable: measured on one event-study design, swapping CRSP for `secd` left Delaware flat at ~2,075 firms while doubling non-Delaware from 968 to 1,923.5657### Format Facts5859- The CIZ format shipped in July 2022 and became the only updated format in February 2025 (December 2024 data was the last SIZ release). Both formats sit in the **same** `crsp` schema in Postgres and the same `crsp` library in SAS — the schema name does not tell you which format you are in. The table name does. Reporting "I queried the `crsp` schema, so this is v2 data" is an unverified claim presented as fact.60- WRDS-built convenience tables keep their legacy names with a `_v2` suffix: `crsp.dsf_v2`, `crsp.msf_v2`, `crsp.stocknames_v2`. CRSP-built tables use the new CIZ names (`crsp.stkdlysecuritydata`). Both are CIZ; the `_v2` ones are pre-joined and wider. Treating the absence of a `_v2` suffix as evidence a table is legacy sends you back to the frozen data.61- On the WRDS Cloud filesystem, SIZ stays at `/wrds/crsp/sasdata/a_stock` and CIZ is at `/wrds/crsp/sasdata/a_stock_v2`.62- Column names carry their frequency as a prefix: `Dly`, `Mth`, `Qtr`, `Ann`. There is no frequency-agnostic `ret` or `prc` in CIZ — `DlyRet` and `MthRet` are different columns in different tables, not the same column read from two files.63- The `62` suffix (`crsp.stkdlysecuritydata62`) is the 1962-start subset product; the `_ind` suffix (`crsp.stkindmembership_ind`) is the full Index database. Stock-only products carry just 4 index series; `crsp.indseriesinfohdr_ind` carries 274. Querying the wrong one returns zero rows rather than an error, so "that index isn't in CRSP" is usually the wrong suffix, not a missing index.6465## Universe Enforcement6667### IRON LAW: NO CIZ COMMON-STOCK SAMPLE WITHOUT ALL FIVE COLUMNS6869<EXTREMELY-IMPORTANT>70Legacy `SHRCD IN (10, 11)` was unpacked into **five** CIZ columns across two tables.71No single column reproduces it.7273```sql74sharetype = 'NS' -- No Special Share Type75AND securitytype = 'EQTY'76AND securitysubtype = 'COM'77AND usincflg = 'Y'78AND issuertype IN ('ACOR', 'CORP')79```8081- `WHERE sharetype = 'COM'` → **WRONG. Returns 0 rows.** `COM` lives at the *SecuritySubType* level; `ShareType` is never `'COM'` in CIZ. CRSP support confirmed this in writing.82- `WHERE securitysubtype = 'COM'` alone → **WRONG.** Picks up non-US-incorporated firms, ADRs (`sharetype='AD'`), and REITs (`issuertype='REIT'`) that legacy `SHRCD` excluded.83- All five, ANDed → **CORRECT.**84</EXTREMELY-IMPORTANT>8586**A universe that silently differs from `SHRCD IN (10,11)` breaks comparability with87every prior paper in the literature — that is an anti-helpful result dressed as a88working query.** The one-column version is faster to type and returns plausible row89counts, which is exactly why it survives review.9091Verified distribution in `crsp.stksecurityinfohist` (2026-07-26): `EQTY/COM/NS/CORP/Y`92= 90,515 rows and `EQTY/COM/NS/ACOR/Y` = 21,682 rows are the two `SHRCD 10/11` cells;93`EQTY/COM/AD/CORP/N` (6,279 ADR rows) and `EQTY/COM/NS/REIT/Y` (2,347 REIT rows) are94what the sloppy filter lets in.9596### Exchange Facts9798- `EXCHCD` is gone. `primaryexch` is a single letter: `N` (NYSE), `A` (NYSE American), `Q` (NASDAQ), `R` (NYSE ARCA), `B` (BATS), `I` (IEX), `C` (Consolidated), `X` (Unknown), `N/A`.99- `EXCHCD IN (1,2,3)` maps to `primaryexch IN ('N','A','Q')` — but `primaryexch` alone also carries the halted and suspended records that legacy `EXCHCD` split into `-2` and `-1`. To reproduce legacy `EXCHCD IN (1,2,3)` exactly, add `conditionaltype = 'RW' AND tradingstatusflg = 'A'`.100- Legacy `EXCHCD = -2` (halted) → `tradingstatusflg = 'H'`. Legacy `EXCHCD = -1` (suspended) → `tradingstatusflg = 'S'`.101- The universe columns live on the **history** table (`stksecurityinfohist`, one row per attribute-change interval), not only the header. Filtering on `stksecurityinfohdr` applies today's classification to the whole 1925–2025 panel and back-fills survivorship into the sample.102103### CUSIP Facts104105- CIZ **inverted the CUSIP naming**. `CUSIP` is now the *historical* CUSIP (legacy `NCUSIP`); `HdrCUSIP` is the *header/most-recent* CUSIP (legacy `CUSIP`).106- Code ported from SIZ that joins on `cusip` therefore changes meaning silently — it starts joining on the historical value. For a point-in-time match to Compustat/IBES this is usually what you wanted; for a header match it is a bug.107108## Return Enforcement109110### IRON LAW: NEVER ADD A DELISTING RETURN TO A CIZ RETURN111112<EXTREMELY-IMPORTANT>113In SIZ, delisting returns lived only in `crsp.dsedelist`/`msedelist` and every114researcher hand-merged them in. **CIZ embeds the delisting return directly in the115daily and monthly return series.**116117Verified for PERMNO 10002 (delisted 2013-02-15):118119| dlycaldt | dlyprc | dlyprcflg | dlyret | dlydelflg |120|----------|--------|-----------|--------|-----------|121| 2013-02-14 | 2.92 | `TR` | -0.010170 | `N` |122| 2013-02-15 | 2.98 | `TR` | 0.020548 | `N` |123| 2013-02-19 | 0.00 | `DA` | **0.010906** | `Y` |124125The 2013-02-19 row *is* the delisting return. `crsp.stkdelists` still exists, but it is126for the delisting *reason* and *event* detail — not for patching the return series.127128- `coalesce(dlyret,0) + coalesce(dlret,0)` → **WRONG. Double-counts.**129- `(1+dlyret)*(1+dlret)-1` → **WRONG. Same double-count, compounded.**130- Use `dlyret` as-is → **CORRECT.**131</EXTREMELY-IMPORTANT>132133**Silently inflating delisting-month returns reintroduces exactly the survivorship134artifact the merge was supposed to fix.** The old merge is muscle memory and the135result looks normal — the bias only shows up in the delisting tail, which is where136the identification usually lives.137138### Return Facts139140- `MthRet` is a **compound of daily returns within the month**, with dividends reinvested on the ex-date. Legacy `RET` was a month-end-to-month-end holding period return with dividends reinvested at month-end. These are different estimators, not a renaming. WRDS found 90 stock-months differing by >100% and 3,479 differing by >5%.141- The same change applies to delisting returns (`DelRet`), where the divergence can be larger.142- `DLRETX` (delisting return without dividends) **does not exist** in CIZ. There is no substitute.143- `DlyRetMissFlg` and `DlyRetDurFlg` explain missing and multi-period returns. `DlyRetDurFlg = 'D1'` is the ordinary adjacent-trading-day case; `P1`–`P9` mean the return spans 2–10 trading periods; `MR` means missing. Filtering on this flag replaces the old ad-hoc "drop returns after a gap" heuristics.144- `DlyPrc` is always positive. The bid-ask-average case that legacy encoded as a negative price is now `DlyPrcFlg = 'BA'`; a real closing trade is `'TR'`; a delisting amount is `'DA'`. Never call `abs()`.145146## What Changed at a Glance147148| Concept | Legacy SIZ | CIZ (v2) |149|---------|-----------|----------|150| Daily price | `prc` (negative = bid/ask avg) | `dlyprc` (always positive) + `dlyprcflg` |151| Daily return | `ret` | `dlyret` (delisting return included) |152| Monthly return | `ret` from `msf` | `mthret` (compounded daily) |153| Common stock | `shrcd IN (10,11)` | 5 columns (see above) |154| Exchange | `exchcd IN (1,2,3)` | `primaryexch IN ('N','A','Q')` |155| Historical CUSIP | `ncusip` | `cusip` |156| Header CUSIP | `cusip` | `hdrcusip` |157| Delisting code | `dlstcd` (3-digit) | `delactiontype`, `delstatustype`, `delreasontype`, `delpaymenttype` |158| Distribution code | `distcd` (4-digit) | `distype`, `disfreqtype`, `dispaymenttype`, `disdetailtype`, `distaxtype`, `disorigcurtype`, `disordinaryflg` |159| Adjustment factors | `cfacpr`, `cfacshr` in `dsf` | `crsp.stkdlycumulativeadjfactor` (separate table) |160| Market index | `vwretd` in `dsf` | `indno=1000200` in `crsp.inddlyseriesdata` |161| Issuer attributes | mixed into `stocknames` | `crsp.stkissuerinfohdr` / `stkissuerinfohist` (PERMCO-keyed) |162163## Table Map164165Most-used CIZ tables. Full catalog with verified columns: `references/tables.md`.166167| Table | Grain | Use for |168|-------|-------|---------|169| `crsp.stkdlysecurityprimarydata` | permno × day, 12 cols | Daily returns/prices/cap — **default daily table**, ~7 GB |170| `crsp.stkdlysecuritydata` | permno × day, 32 cols | Adds bid/ask, high/low, open, prev-price, dividend amounts — ~20 GB |171| `crsp.stkmthsecuritydata` | permno × month, 37 cols | Monthly aggregates + identifiers |172| `crsp.stkqtrsecuritydata` / `stkannsecuritydata` | permno × qtr / year | Pre-aggregated panels; check `qtrcompflg`/`anncompflg` |173| `crsp.stksecurityinfohist` | permno × interval | **Universe filters, historical CUSIP/ticker** |174| `crsp.stksecurityinfohdr` | permno | Current/header attributes only |175| `crsp.stkissuerinfohdr` / `stkissuerinfohist` | permco | Issuer-level SIC/NAICS/ICB, non-duplicated issuer counts |176| `crsp.stkshares` | permno × interval | Shares outstanding history |177| `crsp.stkdistributions` | permno × exdt × seq | Dividends, splits, factors |178| `crsp.stkdelists` | permno | Delisting reason/status detail (**not** for returns) |179| `crsp.stkdlycumulativeadjfactor` | permno × day | `dlycumfacpr`, `dlycumfacshr`, `dlyshrout` |180| `crsp.inddlyseriesdata` / `indmthseriesdata` | indno × period | Index returns and levels |181| `crsp.stkindmembership_ind` | permno × indno | Index constituents (S&P 500 = `indno 1000500`) |182| `crsp.dsf_v2` / `msf_v2` / `stocknames_v2` | WRDS-built | Pre-joined convenience tables (identifiers + data + `shrout` + factors) |183| `crsp.metafileinfo`, `metaiteminfo`, `metaflaginfo`, `metasiztociz` | metadata | Self-documenting schema — query these instead of guessing |184185## Canonical Queries186187All queries below were executed against WRDS PostgreSQL on 2026-07-26. Full set with188output: `references/queries.md`.189190**Common-stock daily panel** (the `SHRCD 10/11` + `EXCHCD 1/2/3` equivalent):191192```sql193SELECT d.permno, d.dlycaldt, d.dlyprc, d.dlyret, d.dlycap, d.dlyvol194FROM crsp.stkdlysecurityprimarydata d195JOIN crsp.stksecurityinfohist h196 ON h.permno = d.permno197 AND d.dlycaldt BETWEEN h.secinfostartdt AND h.secinfoenddt198WHERE d.dlycaldt BETWEEN %(start)s AND %(end)s199 AND h.sharetype = 'NS' AND h.securitytype = 'EQTY' AND h.securitysubtype = 'COM'200 AND h.usincflg = 'Y' AND h.issuertype IN ('ACOR','CORP')201 AND h.primaryexch IN ('N','A','Q')202 AND h.conditionaltype = 'RW' AND h.tradingstatusflg = 'A';203```204205The `BETWEEN secinfostartdt AND secinfoenddt` join is mandatory — it is what makes the206classification point-in-time. Dropping it applies the security's final classification207to its entire history.208209**Market capitalization** — do not compute it. `dlycap` (and `mthcap`) is CRSP's own210capitalization in **$ thousands**, already on the row. `dlyprc * shrout` reintroduces211the precision and rounding differences CRSP documented.212213**Market index return** — join on `indno`, do not look for `vwretd`:214215```sql216SELECT m.permno, m.mthcaldt, m.mthret, i.mthtotret AS vwretd, i.mthprcret AS vwretx217FROM crsp.stkmthsecuritydata m218JOIN crsp.indmthseriesdata i ON i.mthcaldt = m.mthcaldt AND i.indno = 1000200;219```220221`1000200` = CRSP NYSE/NYSEMKT/Nasdaq/Arca Value-Weighted (`vwretd`/`vwretx`),222`1000201` = Equal-Weighted (`ewretd`/`ewretx`), `1000502` = S&P 500 Composite223(`sprtrn` = `dlyprcret`/`mthprcret`).224225**Compustat merge** — the CCM link is **unchanged** by CIZ. `crsp.ccmxpf_lnkhist` is226still keyed on `lpermno`, so existing CCM code ports as-is once the CRSP side is CIZ.227228## Additional Resources229230- **`references/tables.md`** — full CIZ table catalog, verified column lists, grain and key columns231- **`references/siz-to-ciz.md`** — column-by-column crosswalk from every legacy SIZ file232- **`references/flags.md`** — all 774 flag values across 62 flag types, dumped from `crsp.metaflaginfo`233- **`references/known-differences.md`** — WRDS/CRSP-documented value discrepancies and the monthly-return methodology change234- **`references/queries.md`** — verified query recipes (universe, delisting, factors, indexes, CCM, MSE-style rebuilds)235- **`references/indexes.md`** — INDNO/INDFAM conventions, the +400 monthly rule, S&P 500 series, decile statistics236- **`examples/ciz_panel.py`** — end-to-end Python pull of a CIZ common-stock panel237- **`${CLAUDE_SKILL_DIR}/../crsp-lseg-splice/SKILL.md`** — CRSP updates annually, so the CIZ daily file stops at the last December. That skill carries the panel forward to T-1 with LSEG via CUSIP→RIC, and has the measured coverage (~91% of the common-stock universe) and the two splice hazards (adjustment basis, foreign-venue RICs).238- **`${CLAUDE_SKILL_DIR}/../../skills/wrds/SKILL.md`** — connection, `.pgpass`, WRDS Cloud/SGE rules (this skill assumes them)239- CRSP source PDFs (WRDS login required): [User Guide](https://wrds-www.wharton.upenn.edu/documents/1996/CRSP_US_Stock__Indexes_Database_Guide_Flat_File_Format_2.0.pdf), [Cross-Reference Guide](https://wrds-www.wharton.upenn.edu/documents/1942/CRSP_Cross_Reference_Guide_1.0_to_2.0.pdf), [Metadata Guide](https://wrds-www.wharton.upenn.edu/documents/1941/CRSP_Metadata_Guide_Flat_File_Format_2.0.pdf), [Executive Summary](https://wrds-www.wharton.upenn.edu/documents/1943/Executive_Summary_File_Format_1.0_SIZ_to_File_Format_2.0_CIZ.pdf)240- WRDS transition pages: [Announcement](https://wrds-www.wharton.upenn.edu/pages/data-announcements/changes-to-crsp-data/), [Transition FAQ](https://wrds-www.wharton.upenn.edu/pages/support/manuals-and-overviews/crsp/stocks-and-indices/crsp-ciz-faq/), [Index Overview](https://wrds-www.wharton.upenn.edu/pages/support/manuals-and-overviews/crsp/stocks-and-indices/siz-to-ciz-wrds-overview-of-index/), [Recreate MSE Tables](https://wrds-www.wharton.upenn.edu/pages/support/manuals-and-overviews/crsp/stocks-and-indices/recreate-legacy-mse-style-tables/)