The Delaware Court of Chancery on Thursday ordered Palantir Technologies Inc. to turn over corporate records to a company run by Marc Abramowitz, in an unusual court battle that highlights the growing animosity between the reticent Silicon Valley firm and one of its biggest early investors.

Vice Chancellor Joseph R. Slights III said in a 50-page memorandum opinion that Abramowitz had demonstrated a proper purpose of investigating potential fraud and mismanagement in the private software company, which specializes in big data analytics.