What the PCAOB changed
QC 1000 is the PCAOB’s quality control standard. It tells a registered audit firm how to build and run the system meant to keep its audits good. The standard sets who owns which role, how the firm finds and answers risks in its own practice, and how it checks each year that the system works. The Board adopted it in 2024 and it takes effect on 15 December 2026.
On 9 September 2026 the Board voted to narrow it. That vote does not change the standard on its own. A PCAOB rule takes effect only when the SEC approves it, which is why the Board filed the amendments and why the Commission is taking comment on them. Everything below is what would change if the Commission approves the amendments.
The design-only requirement would be rescinded. As QC 1000 stands, a registered firm with no issuer audits must still design a full QC system in case it takes one on, and about 734 firms fall into that group. The External QC Function would be rescinded with it. The largest firms are to appoint an outside body to oversee their QC system, and the Board estimates that requirement applies to 13 firms, those filing more than 100 issuer audit reports in 2025.
The remaining changes are narrower. Documentation retention would fall from seven years to five, and a firm would select its own date for the annual evaluation of its QC system, which the standard currently fixes at 30 September. The named QC roles could be divided among several people or assigned to a person outside the firm. A firm that identifies a deficiency on one engagement would have to look for the same problem on others only where it could have produced insufficient evidence or a wrong conclusion.
The dates
The SEC published the notice in the Federal Register on 18 September 2026. Both deadlines run from that date. Comments are due 21 days later, on 9 October. The Commission has 45 days from publication, to 2 November, to approve the amendments, disapprove them or institute proceedings, and it may take up to 90 days if it publishes its reasons.
QC 1000 takes effect on 15 December 2026 regardless of the outcome. If the Commission approves the amendments, they take effect the same day. If it does not, the standard as adopted in 2024 applies from that date, including the External QC Function.
The Board also asked the Commission to apply the amendments to audits of emerging growth companies. Without that, a firm auditing both would run two versions of its QC system. The Board counts 203 firms that audit both, and between them they audit about 97 percent of EGCs.
Corviniti helps companies prepare for a PCAOB audit
QC 1000 binds audit firms. It sets nothing for the companies they audit. A company encounters the standard through its own audit. A firm operating a tighter quality system plans earlier, requires more documentation behind a judgement, and expects the support for a figure in the financial statements to be identified and available. None of the amendments above alter that, because the standard takes effect in December regardless.
The company’s accounting team does that work, during the year-end close. Corviniti does it with them. We produce the schedules and support an auditor requests and answer the questions that follow, which is PCAOB audit support. We write the technical position papers behind judgement areas such as revenue, impairment and share-based payment, so that a conclusion has a documented basis before the auditor requests one. Where a company also carries SOX obligations, we help with the controls and the evidence supporting them.
Audit firms have had two years to prepare for QC 1000. Audits planned after 15 December 2026 are conducted under it.