Two top proxy advisors were subpoenaed by Masimo under pressure from activists for private communications with investors.

• Masimo issued a subpoena to Glass Lewis and ISS for their private communications with shareholders regarding the upcoming proxy battle between Masimo and activist investor Politan Capital.
• Quentin Koffey, a board member of Masimo, has initiated a proxy fight to secure two additional seats for his firm, Politan.
• The subpoena was made as part of ongoing litigation between Masimo and Politan.

According to sources, ISS and Glass Lewis were subpoenaed for their private communications with investors regarding the upcoming proxy contest with Politan Capital.

Politan Capital was sued by a medical device company earlier this summer, and Masimo founder Joe Kiani, a close friend of President Joe Biden, has characterized the upcoming vote as existential.

At least some of the affected investors were informed about the subpoena disclosed by Glass Lewis, but it was unclear if ISS had done the same, according to people. ISS declined to comment, and Glass Lewis did not respond to CNBC's request for comment.

Kiani's governance of Masimo was criticized by ISS and Glass Lewis, who recommended shareholders vote to elect two directors proposed by Politan. The company sued Masimo the same day the recommendation was made, with Masimo accusing Politan of misleading shareholders and manipulating the situation. Politan denies these allegations.

The annual meeting of Masimo was initially set for July 25, but it was later rescheduled for September following a negative report from ISS. Since then, Masimo and Politan have been involved in legal disputes in Delaware and California.

Shareholders are consulted by ISS and Glass Lewis before recommendations are made, which, although not binding, can significantly influence their voting decisions at numerous companies.

The latest development in a two-year saga is a subpoena issued to Masimo, which has been embroiled in a proxy fight with Politan. The fight between the two companies in 2023 was marked by bitter commentary and controversial tactics from management. This year, Politan accused an associate of Kiani's of buying Masimo shares, voting those shares in favor of Kiani, and then exiting its position. This maneuver, carried out by RTW Investments, was flagged as a potential concern by Glass Lewis and cited by Masimo when it rescheduled its annual meeting.

Masimo's rescheduled investor meeting was deemed unjustifiable by Politan, who pointed out that it violated its own bylaws and came after two negative reports from Glass Lewis and ISS.

CNBC was referred to public legal filings by Politan, but he declined to provide additional comment. Masimo's spokesperson did not immediately respond with a comment.