OSIsoft, LLC is a manufacturer of application software for real-time data management, called the PI System. Founded in 1980, OSIsoft was privately held and headquartered in San Leandro, California. In August 2020, it was announced that the UK-based production company AVEVA agreed to buy OSIsoft in a deal worth $5 billion; the purchase was subsequently completed on 19 March 2021 for a final consideration of £3,831.4 million.