When the CIK changes and the company doesn't
The SEC identifies every filer by its CIK, and almost every financial database inherits that key. But a CIK belongs to a legal entity, not to a business. When a company reorganizes under a new holding company or moves its incorporation, the new entity gets a new CIK and the old one goes quiet. We found 136 companies spread across 277 CIKs, including Alphabet, Exxon Mobil, Cigna, Broadcom, Disney and Medtronic.
Why the CIK changes
Three kinds of corporate housekeeping produce a new CIK while the business carries on unchanged:
- A new holding company. Google Inc. became a subsidiary of the new Alphabet Inc. in October 2015; Disney created a new parent during the Fox deal in 2019; ExxonMobil Holdings Corp took over the XOM listing on 1 July 2026.
- A move abroad, or back. Medtronic (Ireland, 2015), Eaton (Ireland, 2012) and Accenture (Bermuda to Ireland, 2009) each became a new legal entity. Marvell moved from Bermuda to Delaware in 2021.
- A merger that keeps one side's business. Avago bought Broadcom in 2016 and took its name, then moved to the US in 2018. One company, three CIKs.
Typically the new entity files an 8-K12B or similar successor-issuer notice, the ticker moves across, and the old CIK stops filing. Nothing about the business changed. The SEC data, keyed on CIK, now has two companies.
What breaks if you key on CIK
Quarters of Google/Alphabet history a backtest could see, at each quarter end
Point-in-time: a quarter counts once every field in its row was public.
1. The company has no history. At the end of 2015, Alphabet's own CIK had one quarter of public data. Anything that needs a lookback (year-over-year growth needs five quarters, three-year growth thirteen) is missing for one of the largest companies in the market, or has to wait for Alphabet to file comparatives years later. Keyed on the company, the full history was public all along: Google Inc. had filed it.
2. A reorganization looks like a delisting. A survivorship-bias-free universe keeps companies that stop filing. Keyed on CIK, Google Inc. "stopped filing" in October 2015. A backtest records an exit, exactly like a bankruptcy or an acquisition, and a brand-new company appears in its place. 141 of these ghost exits sit in SEC data.
3. The history is duplicated. A new holding company's first annual report repeats the old company's figures as comparatives, filed months or years after they were first public. Keep both copies and the quarter is double-counted; keep only the new CIK's copy and the numbers are dated too late.
The largest companies that changed CIK
By revenue. Each link cites the successor-issuer filing and the ticker moving across.
| Registrants, in order (CIK) | CIK changed | varve_id |
|---|---|---|
| GOOGLE INC. 1288776 → Alphabet Inc. 1652044 | 2015-10-02 | VD1288776 |
| EXXON MOBIL CORP 34088 → ExxonMobil Holdings Corp 2115436 | 2026-07-01 | VD34088 |
| Cigna Holding Co 701221 → Cigna Group 1739940 | 2018-12-20 | VD701221 |
| Avago Technologies LTD 1441634 → Broadcom Pte. Ltd. 1649338 → Broadcom Inc. 1730168 | 2016-02-02, 2018-04-04 | VD1441634 |
| TWDC Enterprises 18 Corp. 1001039 → Walt Disney Co 1744489 | 2019-03-20 | VD1001039 |
| BUNGELTD 1144519 → Bunge Global SA 1996862 | 2023-11-01 | VD1144519 |
| Oracle Systems 777676 → ORACLE CORP 1341439 | 2006-02-06 | VD777676 |
| ACCENTURE LTD 1134538 → Accenture plc 1467373 | 2009-09-01 | VD1134538 |
| Apollo Asset Management, Inc. 1411494 → Apollo Global Management, Inc. 1858681 | 2022-01-03 | VD1411494 |
| MEDTRONIC INC 64670 → Medtronic plc 1613103 | 2015-01-27 | VD64670 |
| Ferguson (Jersey) Ltd 1832433 → Ferguson Enterprises Inc. /DE/ 2011641 | 2024-08-01 | VD1832433 |
| EATON CORP 31277 → Eaton Corp plc 1551182 | 2012-12-04 | VD31277 |
What we deliberately don't link
Linking too much is as bad as linking too little. A merger of two companies has two predecessors and stays separate. So do acquisitions, spin-offs, SPAC deals, and tickers that pass to a different company: BBBY now belongs to the company formerly called Overstock, not to Bed Bath & Beyond. One case we caught while building this: M.D.C. Holdings (the homebuilder, MDC, bought by Sekisui House in 2024) and MDC Partners (the ad agency, MDCA, now Stagwell) are unrelated companies whose tickers make them look like one. Matching on tickers alone would have joined them.
How varve_id works
Every company-level table in Varve Fundamentals, Varve Events and Varve Corporate Actions carries varve_id: "VD" plus the CIK of the first entity in the company's chain. A company that never changed CIK is simply VD + its CIK. The company_lineage table lists every link with its date, the filing that proves it, and whether the ticker moved. In the quarterly and annual tables, lineage_primary marks the row filed first for each company and period, so there is one row per quarter, dated when it first became public.
import pandas as pd
q = pd.read_parquet("varve_fundamentals_quarterly.parquet")
alphabet = q[(q.varve_id == "VD1288776") & q.lineage_primary].sort_values("period_end")
# one unbroken series: Google Inc. through Q2 2015, Alphabet Inc. after, each row dated by its first filing
Notebook 05 in the example notebooks walks through Alphabet and Disney on the free sample. Explore any company's joined history on its page, for example Alphabet or Broadcom.
One id per company, in every table
varve_id ships with Varve Fundamentals and Varve Events, with the evidence for every link.