Although the cost of complying with rigorous Sarbanes-Oxley rules have fallen, audit fees in the US have increased.

A survey by law firm Foley & Lardner shows that in 2006, audit fees rose 4% for mid-sized companies, 5% for small companies and about 6% for Standard & Poor's 500 companies, which includes many of the largest US companies.

Audit fees have risen consistently since 2001, with an average increase of 5% in 2006 and 3% in 2005, compared with a dramatic 67% increase in 2004 when internal control audits were phased in for public companies.

The study reveals that in 2006, companies with less than $1bn in annual revenues spend about $2.82m annually on governance and compliance work.

The figures are up from 2005, when the same companies spent $2.79m on those costs, but also is down from a 2004 peak, when costs were calculated at $3.44m, Reuters.com reported.

Further reading:

Sarbanes-Oxley costs fall but audit fees still up