An asset manager, Ancora, is challenging Nippon Steel's proposed takeover of U.S. Steel, calling for new leadership at the steelmaker after acquiring a small stake in the company. U.S. Steel is one of the major producers of steel in the U.S., employing more than 20,000 people in this a strategically important industry.

An asset manager is seeking to quash Nippon Steel’s takeover of U.S. Steel and oust the leadership of the U.S. steelmaker after taking a stake in the company