We cannot impose the same size thresholds on other audit firms because the sales and assets of non-LLP firms are not
disclosed as they are not required to file their financial statements. Instead, we require that the audit firms undertake at
least 100 audit engagements in one or more of the sample years. This sampling restriction yields a total of 97 audit firms.
Next, we delete from the entire sample period any company audited by Andersen. We delete such companies because
otherwise there would be a mechanical increase in the number of audits by other audit firms, following Andersen’s
disappearance in 2002. We also exclude KPMG because it was already a limited liability company before the introduction of the LLP Act. (Untabulated tests reveal that all of the main results are unchanged if we include Andersen and KPMG in
the sample.) This leaves a final sample of 95 audit firms of which 57 auditors retain unlimited liability while 38 adopt LLP
status. The adopting group consists of 32 LLP firms that file audited financial statements, plus another 6 LLP firms that file
financial statements but are not large enough to qualify for a mandatory audit.