PurposeThe Dodd–Frank Act of 2010 exempts small, non-accelerated filers from compliance with Sarbanes–Oxley Act (SOX) Section 404b internal control audits. However, these firms are required to comply with other internal control regulations, namely, SOX Sections 302 and 404a, starting in 2002 and 2007, respectively. A small number of these firms also voluntarily adopted (and sometimes dropped) Section 404b during 2004-2010. The purpose of this study is to investigate the impact of a series of internal control regulations introduced by SOX on the financial reporting quality of small firms.Design/methodology/approachThe research design for this study is empirical. Using unsigned and signed discretionary accruals as measures of financial reporting quality, the authors compare the financial reporting quality for adopters and non-adopters across four regulation regimes over the period 2000-2010: PRESOX, SOX 302, SOX 404a and SOX 404b.FindingsThe results indicate that most of the adopters and non-adopters benefited from SOX 302 and 404a compared with the PRESOX period. However, only the non-adopters gained incrementally when moving from SOX 302 to SOX 404a. Also, Section 404b benefited firms with material weaknesses, as well as firms without material weaknesses that had the lowest reporting quality, in the PRESOX period.Research limitations/implicationsThis study helps inform the important policy debate on whether to increase the threshold that is used for the SOX 404b exemption. It shows incremental benefits for firms that adopted Section 404b audits, even when they were complying with Section 302 and Section 404a. Consequently, extending the exemption to more companies would result in a loss of the reporting quality benefit of 404b.Originality/valueThis study contributes to the literature by focusing exclusively on non-accelerated filers and by examining differences across four regulation regimes over a long window compared to prior studies. It provides evidence that the financial reporting benefit of SOX 404b is not transitional, but rather extends for a few years even after some firms discontinued the 404b audits.