NEW YORK — The head of an Oregon investment research firm pleaded guilty to insider trading Wednesday, admitting he enticed employees of public companies to feed him secrets he then sold to hedge funds and money managers, as if they resulted from legitimate research.

John Kinnucan, 55, entered the plea to conspiracy to commit securities fraud and two counts of securities fraud, agreeing in a plea deal to serve four to five years in prison. Otherwise, the charges would have carried a potential prison term of up to 45 years.

The calculation includes time for threats Kinnucan made to prosecutors, FBI agents, and a witness during the investigation of his company, Broadband Research LLC. The government said he made nearly 25 phone calls with references to genocide and sexual and other violence.