Corporate lawyers are used to combing through financial statements, contracts and other documents looking for possible risks in mergers and acquisitions and IPOs. But when it comes to reputational risk, clues are often buried in places that lawyers don't traditionally look.

All it takes is one weak link—in a supply chain agreement or a board member's past bad behavior—to break the chain and blow up a company's reputation.

With the increased focus on environmental, social and governance (ESG) issues, lawyers are having to look further and dig deeper into various aspects of deals.