Who is this article for?

Researchers and analysts who need to track audit firms across name changes, mergers, and acquisitions.

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Ideagen Audit Analytics preserves auditor names and keys as they existed at the time of each record, with restructuring events creating new firm iterations that can be linked through the Auditor Events database.

This article explains the process in more detail.

Overview

Researchers building time-series datasets frequently encounter firms that have changed names or been absorbed into other entities. Because each firm iteration has its own auditor key, a firm that changed its name in 2015 will appear under two different keys in the data: one for records before the change and one for records after. Without using Auditor Events to bridge those keys, firm-level aggregations can produce broken or incomplete results: it may appear as if a new firm appeared out of nowhere, or that an existing firm suddenly lost all its clients.

Tracking firm iterations

Every audit firm in Ideagen Audit Analytics, including each version of a firm after a restructuring event, has its own auditor key. Historical records (audit opinions, auditor changes, audit fees) are tagged to the key that was active at the time, based on the name that appeared in the relevant disclosure. Records before the restructuring reference the predecessor key; records after reference the successor key.

Example

Dale Matheson Carr-Hilton LaBonte LLP (auditor key 1470) changed its name to DMCL LLP (auditor key 35889) on 3 December 2025. Audit opinions signed before that date carry key 1470; opinions signed after carry key 35889. The firm's prior and current names are distinct entries in the data.

Using Auditor Events to bridge keys

The Auditor Events database records the formal relationships between predecessor and successor firm iterations. Each event record links two auditor keys and includes the event date and type:

• Name Change - A firm operating under a new legal or trade name
• Merger/Acquisition - One firm absorbing or combining with another
• Split - A firm dividing into separate entities
• PCAOB ID Change - A change to a firm's PCAOB registration identifier

For the DMCL example above, the name change record in Auditor Events links key 1470 (Dale Matheson Carr-Hilton LaBonte LLP) to key 35889 (DMCL LLP) with the 3 December 2025 date. You can use this to identify that these two keys represent the same firm at different points in time and construct a continuous firm-level history accordingly.

To access Auditor Events data, go to the Audit Firm Events search on the Ideagen Audit Analytics platform. Alternatively, you can use Feed 86 (AUDITOR_EVENTS).

Viewing restructurings

The header section of an auditor profile on the platform shows general firm information including current auditor name, which is pulled from the Engagements database and reflects the firm's name as of today.

However, within each database section of the profile, records follow the rules of that database - so the Audit Opinions section will show the signing firm's name as it appeared in the opinion, and the Audit Fees section will show the firm name as of that fee record.

The current name in the header and the historical names in the database sections may differ for firms that have undergone restructurings.

Tracking affiliates and network firms

For the Big Four (Deloitte, EY, KPMG, PwC) and Grant Thornton, non-US member firms are tracked as Audit Affiliates - separate profiles representing individual national or regional member firms. Restructurings specific to one national affiliate are captured in Auditor Events at the affiliate level, not at the global network level.

For other audit networks (RSM, BDO, Forvis Mazars, and others), individual firms are tracked with a Network field indicating membership. These firms are not tracked as affiliates, and their restructurings are captured in Auditor Events at the firm level.

Coverage limitations for historical data

Auditor Events data is maintained on an ongoing basis, but the ability to source information about historical restructurings diminishes for older periods. Information for pre-2014 firm changes can be difficult to locate, and pre-2006 data is sparse - particularly for firms that no longer exist in any form.

Note

Researchers working with older data should be aware that some restructurings from this period may not be fully represented in Auditor Events.

Looking up restructuring history

To review a firm's restructuring history:

1. Navigate to the firm's auditor profile.
   Alternatively, use the Audit Firm Events search.
2. Review the events listed to see name changes, mergers, or other restructurings and their dates.
3. Note the associated auditor keys for each iteration of the firm.

Building a complete firm-level history programmatically

To construct a continuous firm history:

1. Identify the auditor keys for the firm iterations you are working with (from Audit Opinions, Auditor Changes, or other databases).
2. Use Feed 86 (AUDITOR_EVENTS) to map predecessor keys to successor keys.
3. Combine records across keys using the event dates to correctly attribute historical engagements.