What Is Material Nonpublic Information (MNPI)?
Material nonpublic information is any fact about a company that has not been publicly disclosed and that would likely influence a reasonable investor's decision or move the stock price. Under the standard drawn from the Supreme Court's TSC Industries and Basic decisions, information is material if there is a substantial likelihood a reasonable shareholder would view it as significantly altering the total mix of available information.
Common examples include upcoming earnings results that differ from expectations, pending mergers or acquisitions, major contract wins or losses, regulatory decisions such as FDA drug approvals, unannounced executive departures, and looming bankruptcy filings. Information stops being nonpublic once it is broadly disseminated, through a press release or SEC filing, and the market has had time to absorb it.
How Firms Control MNPI
Investment banks constantly hold MNPI because advising on deals requires it, so they separate the private side, including M&A and capital markets bankers, from the public side, including research analysts and traders, with information barriers, often called Chinese walls. When a public-side employee needs deal information, compliance formally brings them over the wall, restricting their trading and communications. Firms also maintain watch lists and restricted lists that block trading and research coverage in names where the bank holds sensitive information.
Regulation FD, adopted in 2000, extends the discipline to issuers themselves: when a public company shares material information with analysts or investors, it must disclose it to everyone simultaneously. On the buy side, funds must police expert networks, channel checks, and conversations with management, since research that crosses from mosaic-building into obtaining MNPI has produced major enforcement cases, including the crackdown on SAC Capital, which paid $1.8 billion in 2013.
Why MNPI Matters
MNPI is the dividing line between legitimate research and a felony. The mosaic theory permits analysts to assemble nonmaterial scraps of public and private information into a valuable conclusion, but a single piece of true MNPI in the mosaic can taint a trade. Because materiality is judged in hindsight, often after the stock has moved, compliance departments train employees to treat borderline information conservatively.
New analysts in banking encounter MNPI in their first weeks, from live deal terms in a data room to draft earnings materials, and their firms require preclearance of personal trades along with strict confidentiality. Mishandling MNPI, even without trading on it, can breach engagement letters and securities law. Knowing how to define materiality and describe an information barrier is a common compliance-oriented interview topic.
