In a six page PDF well worth the read, Arnold & Porter partner and former head of the Market Abuse Unit of the SEC’s Division of Enforcement notes: “The SEC Is Cracking Down On Insider Trading By Lawyers” —

• “A recent series of insider trading actions charging senior lawyers in legal departments of prominent public companies suggests that insider trading by lawyers may be on the rise.”
• “Over the past several months, the U.S. Securities and Exchange Commission has brought enforcement actions charging insider trading in advance of earnings announcements by senior lawyers at Apple and SeaWorld. In a third action, filed in early May 2019, the general counsel of Cintas Corporation was an unwitting victim of a house guest, a lifelong friend, who, the SEC alleges, surreptitiously pilfered merger related information from a folder in the lawyer’s home office.”
• “These actions are noteworthy not only for the brazenness of the conduct involved,
  but because they suggest that insider trading by lawyers remains a ‘profound problem.'[1] And, as the case of the Cintas general counsel demonstrates, innocent lawyers may also fall prey to others, such as close friends and family, looking to exploit their access to material nonpublic information, or MNPI.”
• “In recent years, however, a new wave of enforcement actions, coupled with the SEC’s development of new technology, and its adoption of the trader-based approach[3] to insider trading investigations, has rekindled the question of whether companies and law firms should be doing more to protect against the misuse of MNPI by lawyers and legal personnel. Increasingly, the SEC has touted its use of data analysis to identify patterns of suspicious trading and relationships… Because legal departments and law
  firms are repositories of large amounts of MNPI, they are among the first places that regulators look to determine whether a lawyer is the source of prohibited information.”
• Improved Controls Over MNPI: “Law firms and legal departments should revisit their insider trading policies and procedures and consider whether improvements can be made for how they handle MNPI. The use of project code words for transactional matters is generally effective at protecting against
  disclosure of the identities of the parties to the transaction. The risk of disclosure, however, increases if members of the deal team are inconsistent in their use of code words.[18]”
• Similarly, where law firm attorneys and legal personnel share information in connection with running conflict of interest checks, there is an increased risk of such information being misused. Adopting procedures to shield incoming public company transactional matters from firmwide disclosure can reduce the number of attorneys and employees exposed to MNPI.”
• File Access on a Need-to-Know Basis: “When new project files or client file directories are established, law firms and legal departments should
  consider restricting access to persons on a need-to-know basis. Establishing a permissions process will
  prevent employees who are outside the deal team or earnings process from being able to access file
  folders concerning MNPI.”