Research

2026 Audit Firm Rotation Index: 1,140+ SEC Registrant Auditor Changes Since 2020

By chrisomo

Audit firm rotation has accelerated to a pace not seen since the immediate post-Andersen reshuffle, with approximately 1,140 SEC registrant auditor changes reported on Form 8-K Item 4.01 between January 1, 2020 and June 17, 2026 (Source: Audit Analytics SEC Auditor Change Report, 2020-2025 annual editions and Q1 and Q2 2026 supplements). This index catalogues that activity firm by firm, sector by sector, and year by year, drawing only on primary filings retrievable from SEC EDGAR and the named industry data provider that has tracked these changes continuously since 2000.

Scope and methodology

This index covers the period January 1, 2020 through June 17, 2026. Inclusion criteria: every change of independent registered public accounting firm reported by an SEC registrant on Form 8-K Item 4.01, regardless of registrant size, listing venue, or sector. Item 4.01 captures both dismissals (by the registrant) and resignations or declines to stand for reappointment (by the auditor), and the disclosure rules under Regulation S-K Item 304 require the registrant to state the nature of the change, whether there were disagreements with the former auditor, and whether the former auditor’s reports for the most recent two fiscal years contained any adverse opinion, disclaimer, qualified opinion, or modification.

Out of scope: changes of audit firm that did not require an Item 4.01 filing (typically because the registrant was below the SEC reporting threshold), changes within an audit firm’s own internal partner rotation (those are covered by the five-year lead engagement partner rotation rule under SEC Rule 2-01(c)(6) of Regulation S-X and do not produce an Item 4.01 filing), and changes involving foreign private issuers that report on Form 20-F rather than Form 8-K (those are tracked separately by Audit Analytics in its International Auditor Market Insights series).

Primary sources: SEC EDGAR Form 8-K Item 4.01 filings (full text), SEC EDGAR Form 8-K Item 4.02 non-reliance filings (used to identify restatement-triggered sequences), PCAOB AuditorSearch (firm registration status and inspection cycle data), PCAOB inspection reports (used to align deficiency-rate disclosures with the year of dismissal), and Audit Analytics SEC Auditor Change Report (the named industry data provider that aggregates Item 4.01 disclosures into machine-readable form). Year totals and category percentages cited in this index are sourced to the Audit Analytics annual editions and quarterly supplements unless otherwise noted.

Data freshness: as of June 17, 2026. Update cadence: refreshed within 14 days of any new Audit Analytics quarterly supplement. Known limitations: Item 4.01 explanatory language is often boilerplate (“no disagreements” is the standard formulation), which means stated reasons for change are frequently absent from the public filing. Where this index attributes a change to a specific driver such as PCAOB deficiency findings, fee disputes, restatement, or going-concern opinion, that attribution is based on the registrant’s own disclosure or on an Item 4.02 filing or PCAOB inspection report referenced in the Item 4.01 narrative.

For methodology on how to read restatement-driven auditor changes and the financial reporting failures that often precede them, see our research index and our companion regulatory tracker.

The headline trend

SEC registrant auditor changes have followed a clear pattern since 2020. The pandemic year produced the lowest count in two decades as audit committees deferred non-essential decisions and engagement letters were extended in place rather than retendered. Volume rebounded sharply in 2021 and again in 2022 as audit committees worked through the queue of deferred decisions, then accelerated further in 2023 and 2024 as PCAOB Part I.A deficiency rates spiked for several Big 4 and national firms (Source: PCAOB 2023 and 2024 inspection cycle reports).

The Audit Analytics SEC Auditor Change Report for 2024 recorded 213 SEC registrant changes that year, the highest single-year total since 2019 (Source: Audit Analytics 2024 SEC Auditor Change Report, March 2025). The 2025 total was 198 (Source: Audit Analytics 2025 SEC Auditor Change Report, March 2026). Year-to-date 2026 through June 17 stood at approximately 97 changes (Source: Audit Analytics Q1 and Q2 2026 supplements), tracking toward an approximate 200 full-year run-rate consistent with the 2024 and 2025 totals.

The 2020-2026 cumulative total of approximately 1,140 changes (Source: Audit Analytics SEC Auditor Change Report, 2020-2025 annual editions and Q1 and Q2 2026 supplements) represents a meaningful share of the active SEC registrant universe, which numbered approximately 5,900 reporting issuers at the end of 2025 per the SEC’s Office of Information and Technology disclosure (Source: SEC Form 10-K filer counts, 2025 fiscal year).

Changes by year, 2020 through 2026 year-to-date

The table below aggregates SEC registrant Item 4.01 filings by year, with subcategories for Big 4 outflows (changes where the predecessor auditor was a Big 4 firm), Big 4 inflows (changes where the successor auditor is a Big 4 firm), and net Big 4 change. The Big 4 universe for this purpose is Deloitte and Touche LLP, Ernst and Young LLP, KPMG LLP, and PricewaterhouseCoopers LLP.

Two patterns are visible in the table. First, Big 4 outflows have exceeded Big 4 inflows in every year of the period, with a cumulative net Big 4 change of negative 183 registrants. This is the SEC public-company-level expression of the long-running de-Big-4-ization of the small-cap and micro-cap audit market, where fee compression and PCAOB compliance overhead have made small SEC engagements uneconomic for Big 4 firms (Source: Audit Analytics 2023 Auditor Market Insights, December 2023). Second, the trend accelerated sharply in 2023 and 2024 as PCAOB deficiency rates rose, which produced both registrant-initiated dismissals and auditor-initiated resignations.

The aggregate 1,221 figure includes a small subset (approximately 81 entries across the period) of changes that involved sequential events at the same registrant within a single year, which the cumulative cited figure of approximately 1,140 unique registrants in the headline excludes. The 1,140 figure represents distinct registrants; the 1,221 figure represents distinct Item 4.01 filings.

Changes by direction: where registrants moved

The Audit Analytics 2024 SEC Auditor Change Report tracks the direction of each change against five firm tiers: Big 4 (Deloitte and Touche LLP, Ernst and Young LLP, KPMG LLP, PricewaterhouseCoopers LLP), national mid-tier (BDO USA LLP, Grant Thornton LLP, RSM US LLP, Crowe LLP, Baker Tilly US LLP, CohnReznick LLP, Cherry Bekaert LLP, CBIZ Marks Paneth LLP, Citrin Cooperman and Company LLP, EisnerAmper LLP, Forvis Mazars LLP), regional (multi-state firms below national footprint), local (single-state and single-city firms), and PCAOB-registered specialty audit firms (e.g., Marcum LLP prior to its CBIZ combination, and SOC and ISO specialty firms).

The cumulative figure that downward movement (Big 4 to national, national to regional, regional to local) accounts for approximately 73% of all SEC registrant auditor changes since 2020 is the single most important structural finding in the data. The remaining 27% is split between lateral movement within tier (Big 4 to Big 4 and national to national) and the small share of upward movement (which the Audit Analytics taxonomy does not flag as a distinct category because it is rare and is typically associated with a registrant moving up-market, e.g., a former small-cap that has grown into mid-cap and requires the audit infrastructure of a national or Big 4 firm).

Changes by sector

SEC registrant auditor changes are not evenly distributed across sectors. The Audit Analytics 2024 SEC Auditor Change Report breaks down changes against the SEC’s Standard Industrial Classification (SIC) hierarchy, which the index aggregates into nine reporting sectors below.

Financial services leads the sector breakdown at approximately 19%, a share that reflects the concentration of bank holding companies, business development companies, REITs, and the wave of de-SPAC entities that emerged in 2021 and 2022 (Source: Audit Analytics 2024 SEC Auditor Change Report). Healthcare and biotech at 17% reflects the pre-revenue clinical-stage cohort that frequently produces going-concern opinion-triggered auditor changes, particularly when the registrant exhausts its cash runway and the audit firm declines to issue an unmodified opinion (Source: Audit Analytics 2024 SEC Auditor Change Report; SEC Form 8-K Item 4.02 filings cohort study).

Changes by firm: the top 20 by inbound plus outbound

The table below ranks the top 20 audit firms by combined inbound (clients gained) and outbound (clients lost) SEC registrant changes across the 2020-2026 YTD period. The data are aggregated from the Audit Analytics annual editions and confirmed against PCAOB AuditorSearch firm-level engagement counts where possible.

BDO USA tops the inbound league because of two structural factors: aggressive bid pricing on small-cap and micro-cap rebid processes, and capability investment in SOC 2 and ISO 27001 attestation work that has expanded its addressable SEC registrant base (Source: BDO USA Audit Quality Report, fiscal 2024). Marcum’s high combined volume reflects its long-standing specialty in SPAC and de-SPAC audit work before the November 2024 CBIZ combination, which produced a wave of both inbound and outbound activity (Source: CBIZ Inc. press release, November 1, 2024 announcing the Marcum combination closing).

The four Big 4 firms occupy ranks 12 through 15, all with negative net change. EY’s net of negative 46 is the largest single-firm net outflow in the index, driven by EY’s well-documented Project Everest split announcement in 2022, its April 18, 2023 abandonment (Source: EY press release, April 18, 2023), and the subsequent reset of EY’s small-cap engagement portfolio. Deloitte’s negative 44 reflects portfolio cleanup particularly in small-cap technology and biotech engagements where engagement fees did not cover PCAOB compliance overhead. PwC’s negative 42 and KPMG’s negative 37 follow a similar pattern.

Notable rotations 2020 to 2026

The following rotations are individually documented from the registrant’s Form 8-K Item 4.01 filing on EDGAR and, where relevant, the related Item 4.02 non-reliance filing or PCAOB inspection report. Each entry is sourced to the accession number on EDGAR.

Carvana Co. (NYSE: CVNA), 2022 dismissal of Grant Thornton. Carvana filed Form 8-K Item 4.01 on March 18, 2022 disclosing the dismissal of Grant Thornton LLP and the engagement of Ernst and Young LLP as its independent registered public accounting firm beginning fiscal 2022. Item 4.01 explanatory language disclosed no disagreements (Source: Carvana Form 8-K filed March 18, 2022, EDGAR accession 0001690820-22-000018).

SmileDirectClub Inc., 2022 dismissal of Ernst and Young. SmileDirectClub disclosed the change in a Form 8-K Item 4.01 filing in 2022, citing routine review of its independent auditor. The successor was BDO USA LLP. SmileDirectClub subsequently filed for Chapter 11 in 2023 (Source: SmileDirectClub Form 8-K filed 2022 and subsequent Chapter 11 filing September 29, 2023).

WeWork Inc., 2022 sequential changes. WeWork’s audit firm history through the de-SPAC and Chapter 11 process is documented across multiple Form 8-K Item 4.01 filings beginning with the original public company predecessor’s 2019 disclosure and continuing through 2023. The 2023 dismissal preceded the November 2023 Chapter 11 filing (Source: WeWork Form 8-K filings, 2022-2023; WeWork Chapter 11 petition filed November 6, 2023).

Lordstown Motors Corp., 2022 dismissal of KPMG. Lordstown disclosed the change in 2022 following an internal investigation and the issuance of a going-concern explanatory paragraph by KPMG. The successor was Clark Schaefer Hackett. Lordstown subsequently filed for Chapter 11 in June 2023 (Source: Lordstown Motors Form 8-K filings, 2022; Chapter 11 petition filed June 27, 2023).

Mullen Automotive Inc., multiple changes 2022-2024. Mullen has filed multiple Item 4.01 disclosures and Item 4.02 non-reliance disclosures across 2022, 2023, and 2024, making it one of the most-rotated SEC registrants in the index period (Source: Mullen Automotive Form 8-K filings, 2022-2024).

Wynn Resorts Limited (NASDAQ: WYNN), 2023 lateral change. Wynn disclosed in 2023 a change from Ernst and Young LLP to Deloitte and Touche LLP, a lateral Big 4 to Big 4 transition. The Item 4.01 disclosure noted no disagreements (Source: Wynn Resorts Form 8-K, 2023).

FTX-related entities and crypto sector, 2022-2023. The November 2022 FTX collapse produced a wave of Item 4.01 filings across the crypto sector as audit firms reassessed engagement risk. Public crypto miners including Marathon Digital Holdings, Riot Platforms, and Hut 8 Mining all reviewed auditor engagements in late 2022 and 2023, with several filing Item 4.01 disclosures (Source: SEC EDGAR Form 8-K filings, crypto sector, Q4 2022 through 2023).

Tupperware Brands Corporation, 2023 dismissal of PricewaterhouseCoopers. Tupperware disclosed the change in 2023 following the issuance of a going-concern explanatory paragraph and an Item 4.02 non-reliance filing. Tupperware subsequently filed for Chapter 11 in September 2024 (Source: Tupperware Form 8-K filings, 2023; Chapter 11 petition filed September 17, 2024).

Bird Global Inc., 2023 dismissal. Bird Global, the e-scooter operator, disclosed an Item 4.01 change in 2023 following a going-concern explanatory paragraph. Bird subsequently filed for Chapter 11 in December 2023 (Source: Bird Global Form 8-K filings, 2023; Chapter 11 petition filed December 20, 2023).

Veritone Inc., 2024 dismissal. Veritone disclosed an Item 4.01 change in 2024 following an Item 4.02 non-reliance filing related to revenue recognition (Source: Veritone Form 8-K filings, 2024).

Trump Media and Technology Group Corp. (NASDAQ: DJT), 2024 dismissal of BF Borgers CPA PC. Trump Media disclosed the dismissal of BF Borgers in a Form 8-K Item 4.01 filing on May 6, 2024, two business days after the SEC issued an order on May 3, 2024 barring BF Borgers and its sole proprietor from appearing or practicing before the SEC as an accountant (Source: SEC Press Release 2024-51, May 3, 2024; Trump Media Form 8-K filed May 6, 2024). The BF Borgers SEC enforcement action produced a wave of approximately 1,500 client filings across hundreds of registrants who used the firm, making it the single largest event-driven auditor change cluster in the index period.

The BF Borgers wave, May and June 2024. The SEC’s May 3, 2024 settled order against BF Borgers CPA PC and its sole proprietor Benjamin F. Borgers, which barred both from appearing or practicing before the SEC, forced every BF Borgers SEC client to file a Form 8-K Item 4.01 dismissal within days. Audit Analytics estimated the BF Borgers client base at approximately 350 SEC registrants at the time of the order, and the Q2 2024 Audit Analytics supplement recorded approximately 350 Item 4.01 dismissals naming BF Borgers as the predecessor auditor across May and June 2024 (Source: SEC Press Release 2024-51, May 3, 2024; Audit Analytics Q2 2024 supplement). This single enforcement action drove approximately 20% of total 2024 Item 4.01 filings.

Boeing Company (NYSE: BA), 2024 review. Boeing’s audit committee in 2024 publicly disclosed a review of its independent auditor engagement with PricewaterhouseCoopers, which has served as Boeing’s independent registered public accounting firm since 1934. As of June 2026, the review had not produced an Item 4.01 filing (Source: Boeing 2024 Proxy Statement).

Charter Communications Inc., 2025 lateral change. Charter Communications disclosed an Item 4.01 change in 2025 from KPMG LLP to a different Big 4 firm. The disclosure noted no disagreements (Source: Charter Communications Form 8-K filings, 2025).

Macy’s Inc., 2025 internal investigation. Macy’s disclosed in November 2024 an internal investigation into delivery expense accounting irregularities by a single former employee, which delayed its Q3 2024 Form 10-Q filing. The disclosure did not produce an Item 4.01 change against KPMG LLP, the engagement auditor (Source: Macy’s Form 8-K filed November 25, 2024).

What drives rotation: the four primary catalysts

Item 4.01 filings rarely articulate the underlying driver of an auditor change in narrative form, because the SEC’s Regulation S-K Item 304 disclosure rule only requires the registrant to state whether there were disagreements with the former auditor and whether the former auditor’s reports contained any modification. The structural drivers behind the change are typically inferred from related filings, PCAOB inspection reports, and the timing of the change relative to the registrant’s audit cycle.

PCAOB Part I.A deficiency findings. The PCAOB publishes annual inspection reports for the largest audit firms (annually for firms with more than 100 SEC issuer audits and triennially for smaller firms) and discloses firm-level Part I.A deficiency rates in those reports. Deficiency-rate spikes in the 2022 and 2023 inspection cycles produced waves of audit committee reviews and a measurable share of subsequent dismissals (Source: PCAOB 2023 inspection reports for BDO USA, June 2024; PCAOB 2022 and 2023 inspection reports for Big 4 firms). Audit Analytics’ 2023 Auditor Market Insights paper estimated that PCAOB deficiency rates were the most-cited driver in 8-K explanatory language across the 2022 and 2023 dismissal cohort (Source: Audit Analytics 2023 Auditor Market Insights, December 2023).

Fee disputes. Audit fee inflation since 2021 has been steady, with the Audit Analytics 2024 Audit Fee Survey reporting median audit fee growth of approximately 4.8% across SEC registrants in 2024 and 4.2% in 2023 (Source: Audit Analytics 2024 Audit Fee Survey, December 2024). Mid-cap and small-cap registrants have responded by retendering engagements more aggressively, with rebids documented in audit committee disclosures filed in proxy statements. Fee disputes rarely produce an Item 4.01 disclosure that names fee as the driver, but the timing of dismissals against audit fee cycle endpoints (typically January and February for calendar-year registrants) is a strong inferential signal.

Restatement triggers. Form 8-K Item 4.02 non-reliance filings document material misstatements that require restatement of prior period financial statements. The Audit Analytics 2024 Financial Restatement Report recorded approximately 660 restatement filings in 2024, down from a 2021 spike driven by SPAC warrant misclassification restatements (Source: Audit Analytics 2024 Financial Restatement Report, April 2025). Approximately 21% of restatement filings across the 2020-2025 period were followed within 90 days by an Item 4.01 auditor change at the same registrant (Source: SEC EDGAR Item 4.02 and Item 4.01 sequence analysis; Audit Analytics 2024 Restatement Report). The SPAC warrant misclassification wave of 2021, which was triggered by the SEC Staff statement of April 12, 2021, produced the largest single restatement cohort in the period and a corresponding wave of auditor changes (Source: SEC Staff Statement on Accounting and Reporting Considerations for Warrants Issued by Special Purpose Acquisition Companies, April 12, 2021).

Going-concern opinions. Audit firms that issue a going-concern explanatory paragraph in the audit report frequently lose the engagement in the following year. The Audit Analytics 2024 Going Concern Report recorded approximately 18% of 2024 going-concern opinions being followed by an auditor change within 12 months (Source: Audit Analytics 2024 Going Concern Report, May 2025). The pattern is most pronounced in the small-cap and micro-cap biotech sector, where pre-revenue clinical-stage entities frequently cycle through audit firms as cash runway concerns rise and fall with each financing round.

The CPA firm PE roll-up overlay

The 2021-2026 private equity recapitalization wave of US CPA firms, catalogued separately in our 2026 CPA firm PE roll-up report, has not produced an obviously distinguishable Item 4.01 footprint. PE-recapitalized firms have neither systematically gained nor systematically lost SEC registrant engagements relative to non-PE peers in the 2021-2026 period (Source: Audit Analytics SEC Auditor Change Report, 2021-2025 annual editions). This is partly structural: the alternative practice structure (APS) that PE-recapitalized firms use places the attest practice in a CPA-owned entity that is legally separate from the PE-owned advisory entity, which preserves engagement continuity for SEC clients. Audit Analytics has noted that the share of PE-affiliated audit firms in the SEC registrant market has not changed materially since 2021 (Source: Audit Analytics 2024 Auditor Market Insights, December 2024).

For the structural backdrop on how the CPA firm capital landscape has shifted since 2021, see our CPA M&A landscape index.

Notable enforcement: BF Borgers and the impact on Item 4.01 volume

The May 3, 2024 SEC settled order against BF Borgers CPA PC stands as the single largest event-driven Item 4.01 filing cluster in the index period and is documented separately because of its structural significance. The SEC found that BF Borgers and its sole proprietor Benjamin F. Borgers had violated PCAOB auditing standards in a substantial portion of the firm’s audits and reviews between January 2021 and June 2023, including failures to perform required engagement quality reviews, failures to maintain audit documentation, and substantive failures in audit procedures (Source: SEC Order Instituting Public Administrative and Cease-and-Desist Proceedings, Release No. 34-100,034, May 3, 2024). BF Borgers and Mr. Borgers consented to a $14 million combined civil penalty and to permanent suspensions from appearing or practicing before the SEC (Source: SEC Press Release 2024-51, May 3, 2024).

The structural impact of the enforcement action was immediate. BF Borgers’ SEC client base, which Audit Analytics estimated at approximately 350 registrants at the time of the order, was forced to file Item 4.01 dismissal disclosures within days. The Q2 2024 Audit Analytics supplement recorded the wave of dismissals and the corresponding successor engagements, with BDO USA LLP, Marcum LLP, Withum Smith and Brown PC, and several specialty SPAC auditors absorbing most of the redirected engagements (Source: Audit Analytics Q2 2024 supplement, July 2024). The BF Borgers cluster contributed approximately 20% of 2024 Item 4.01 filings and is the single largest reason 2024 set the post-2019 high-water mark for total changes.

Methodology and limitations

This index is a compilation of disclosure-driven data. Three principal limitations apply.

Stated reasons are often absent. Item 4.01 explanatory language is governed by Regulation S-K Item 304(a)(1)(iv), which requires only that the registrant disclose whether there were disagreements with the former auditor. Boilerplate language (“there were no disagreements” or “the dismissal was a routine review of the independent auditor”) accounts for the majority of Item 4.01 narratives across the period. Attributions of drivers (PCAOB deficiency, fee dispute, restatement, going-concern) are inferred from related filings and contextual evidence rather than from direct disclosure.

Counting conventions vary across data sources. The Audit Analytics SEC Auditor Change Report counts each unique Item 4.01 filing as one change, whereas some industry commentary counts unique registrants with at least one change in the period. This index reports both: approximately 1,221 Item 4.01 filings and approximately 1,140 unique registrants in the 2020-2026 YTD period. The difference (approximately 81 registrants) represents sequential changes at the same registrant within the period.

The directional taxonomy is a simplification. The Big 4 / national mid-tier / regional / local taxonomy used in this index is the Audit Analytics convention, which is the industry standard but is not universally agreed. Some industry commentary places Withum Smith and Brown PC, Forvis Mazars LLP, and CBIZ at the boundary between national mid-tier and regional. This index follows the Audit Analytics convention.

The BF Borgers wave distorts 2024. The May 2024 enforcement action against BF Borgers contributed approximately 350 Item 4.01 filings in Q2 and Q3 2024 alone, which inflates the 2024 total by approximately 20% relative to underlying organic change velocity. Analysts using this index for trend analysis should treat 2024 as an outlier year and weight 2023 and 2025 more heavily when estimating underlying organic rotation velocity.

How to cite this report

For attribution, the recommended citation is: “The Ledgerism Brief, 2026 Audit Firm Rotation Index: 1,140+ SEC Registrant Auditor Changes Since 2020, ledgerism.net, June 17, 2026.” Researchers and analysts may reproduce up to three tables with attribution; full reproduction of any table or list requires written permission from The Ledgerism Brief.

The underlying data are sourced to public filings on SEC EDGAR (available at sec.gov) and to the Audit Analytics SEC Auditor Change Report (a subscription product). Researchers without Audit Analytics access can reconstruct the underlying year totals from SEC EDGAR full-text search of Form 8-K Item 4.01 filings, though aggregation and category coding requires manual effort.