Audit committees looking to reduce their risk of restatement should probably consider engaging a Big 4 firm, but even among the Big 4 there are differences in how likely a given filing will lead to restatement.

Big 4 firms show lower rates of material restatements across capital markets compared with other firms, according the data below provided to Compliance Week by Audit Analytics based on a late January download as the firm prepares its annual restatement study. Material restatements are foretold in Item 4.02 of Form 8-K, where companies indicate they’ve found a mistake so serious investors should not rely on previously published financial statements while the company works on the restatement.

In 2015, for example, Big 4 firms were behind 44 such restatements out of 4,454 filings, for a rate of 0.99 percent. Among national firms Grant Thornton, BDO USA, and RSM, 766 engagements led to 21 restatements in 2015, or 2.74 percent. Audit firms had no comment on the data.

All other firms accounted for 96 restatements out of 3,957 filings, or 2.43 percent. That figure may be skewed somewhat, however, as the “other” category includes filings where companies indicated in their 8-K disclosures that they had no audit firm at the time of filing, either because the firm was dismissed or resigned the engagement.

In the same year, companies restated only four times under KPMG out of 1,256 engagements, for a rate of 0.32 percent. Seven Deloitte clients restated in 2015 out of 1,333 engagements, for a rate of 0.53 percent. At PwC and EY, the numbers were a bit higher. Of 1,540 engagements at PwC, 16 led to restatement, or 1.04 percent. At EY, 17 of 1,525 engagements, or 1.11 percent, led to restatement.

Material restatements overall are declining, as Audit Analytics reported in last year's restatement study and as the next study due out soon will show. In the current data broken down by firm, all Big 4 firms show reduced restatements rates from 2013 to 2015.

At Deloitte, for example, the overall rate has fallen from 0.89 percent in 2013 to 0.53 percent in 2015. At EY, rates fell from 2.34 percent in 2013, a six-year high for the firm, to 1.11 percent. At KPMG, rates feel from 0.92 percent in 2013 to 0.32 percent in 2015. And at PwC, rates fell from 1.6 percent in 2013, also a six-year high for that firm, to 1.04 percent in 2015.

The same is not true for Grant Thornton or BDO USA. At Grant Thornton, restatements of 1.98 percent in 2013 fell to 1.41 percent the following year, then rose to 2.41 percent in 2015. At BDO, restatements held steady from 2013 to 2014, but rose to 4.29 percent in 2015. RSM showed improvement with 0.78 percent in 2014 and none the following year, and the “other” category improved from 2.8 percent to 2.43 percent.