Search this forum for Sarbanes-Oxley. At my interview, the interviewer started nodding immediately when I said this, you really have to know about it.
Couple of points to be made on it that aren’t mentioned - while it has increased the workload (and hence fees) of audit firms, it is an additional burden on the firm in question. This increase in costs could potentially make some firms (that are borderline in their viability) go bust, thereby decreasing the amount of work for audit firms. Ergo it’s a balancing act and it will be interesting to see if SOX is reduced in strength in the future.