Private equity firms are digging deeper into companies they are thinking about buying as they respond to the global crackdown on bribery and corruption and seek to protect their investments and reputations.

As serial acquirers of companies, sometimes with operations in less-transparent emerging markets, firms are having to delve into the backgrounds of an ever-broader range of executives to ensure they comply with far-reaching regulation, including the US Foreign Corrupt Practices Act and the UK's Bribery Act.