When the Securities and Exchange Commission adopted its controversial new whistleblower rules in May, it incorporated language that excludes outside auditors from participating in the program. But now some corporate lawyers say the rules contain plenty of loopholes that auditors could use to bring complaints against clients to the SEC in pursuit of hefty rewards.

The whistleblower program gives anyone with direct knowledge of corporate misdeeds a new financial incentive to report them directly to the SEC. Whistleblowers can earn up to 30 percent of what the agency ultimately collects in sanctions if regulators settle a legitimate violation for more ...