Is there any legal requirement for public companies to have whistle blower hotlines other than the Sarbanes-Oxley Act?

I do not believe any other exists. However it is a good idea to create some sort of process by which individuals that identify fraud or unethical behavior have an internal way to report it, for Senior Management resolution. If people do not have an outlet, to report problems internally, they will probably go external to voice their concerns.

I agree there is no other law if you do not use federal funds. There are requirements if you receive any federal and most state funds to have these hot lines. It is better to identify and solve problems internally before something happens that can cause major issues. There are also lawyers that can suit on behalf of whistleblowers and they make there money on contingent fees from the amount recovered by your organization. If someone feels they have a good case it could cost your organization to defend yourself. Remember these hot lines are not always for financial issues but also danguous production process or creating a product that can harm someone else.

As a part of new-hire orientation, most large organizations are including a training section on where to report unethical business practices, sexual harrassment issues, fraud, and other illegal acts. There is no "law" that I know of that requires a "hotline" but it is in the best interest of the organization to offer such protection to employees as well as the organization.

There are no other requirements expect those in Sarbanes-Oxley. However, you may want to implement this there are other benefits such as the items Christine mentions. We went private in 2006 and still maintain this line. It's been helpful in ensuring improper acts are stopped.

NY stock listing regulations require such a provision, I believe. "Contractual", rather than statutory, as listing is not mandatory. The SEC is developing rules that have whistleblower requirements.