Companies invest in an audit for a number of reasons. Larger companies are required to do so by law, but many would do so anyway even if there were no statutory obligation. An independent audit is crucial to good corporate governance and essential to an effective internal financial control function.
Auditing gives credibility to information provided to shareholders. It shows assurance to investors and other providers of finance who are able to make their decisions in a safe environment, with confidence. Safety and confidence reduce the cost of capital and make companies competitive and profitable.