Robert Boyd wanted to exit from his company. In 2019, he had sold a majority stake in Northern Biomedical Research, Inc. (“NBR”) to the individual defendants in this case: Shane Woods, Dean Haan, Joshua Bartoe, and Mark Johnson. He retained a 16% stake in the business but had moved from its headquarters in Michigan to a ranch in Idaho and had grown increasingly frustrated with the management of the company that he started several decades earlier. At the same time, the individual defendants were seeking to expand. NBR lacked the cash or revenue to fund that expansion, so the defendants began exploring a potential loan, and they also considered equity financing options. But they told Boyd little or nothing about these efforts, particularly with respect to the company’s interest in equity financing and early overtures from Avista Capital Partners, LLP (“Avista”), the venture capital firm that would wind up taking a 50% stake in NBR.

Boyd sold his shares in December 2020 for about $3.4 million, an amount based on an agreed-upon accounting firm’s annual valuation of NBR at roughly $21 million. The next spring, Avista and NBR entered an agreement for a capital infusion of $40 million, thus valuing the company at $80 million. Unhappy that he sold his stake in NBR for less than he might have later received, Boyd sued the company and the individual defendants, alleging that their failure to inform him about their discussions with Avista or the fact that NBR was considering private-equity financing violated securities law and breached the defendants’ fiduciary duties under Michigan common law. After discovery, the district court granted summary judgment to the defendants on all counts. This appeal followed.

We hold that the district court did not err when it granted summary judgment on Boyd’s securities-law claims. But because it applied an incorrect legal standard under Michigan common law, a genuine dispute of material fact remains as to whether Boyd is entitled to relief on Counts III, IV, and V of his second amended complaint. We therefore affirm in part and reverse in part.