The reported $25 million parachute payment Bill O'Reilly received this week upon his ouster from Fox News in the wake of sexual assault allegations has generated plenty of headlines and public outcry. However, it was unlikely to expose the network's parent company to any significant liability from shareholder derivative suits, observers said on Friday.

Though such legal challenges are not uncommon in Delaware, they do raise a difficult set of challenges for shareholders who file lawsuits against corporate directors, on behalf of companies. Under Delaware law, decisions by a corporate board are typically protected by the deferential business judgment rule, which generally prevents courts from second-guessing actions made in the interest of a corporation.

Plaintiffs can plead around the business judgment rule by claiming breaches of fiduciary duty or corporate waste to invoke a less-stringent standard of review, but it is rare that derivative claims survive a motion to dismiss.