Bayer AG won U.S. antitrust approval for its US$66 billion takeover of Monsanto Co., clearing the last major regulatory hurdle along a nearly two-year path toward forming the world’s biggest seed and agricultural-chemicals provider.

The companies reached a settlement with the Justice Department that resolves the government’s concerns that the merger as initially structured would harm competition that benefits consumers and farmers, the U.S. said in a statement Tuesday. The agreement requires the largest sale of assets in a U.S. merger enforcement case, the government said.

"America’s farm system is of critical importance to our economy, to our food system, and to our way of life," said Makan Delrahim, the head of the department’s antitrust division. "American farmers and consumers rely on head-to-head competition between Bayer and Monsanto."

For Bayer, acquiring Monsanto is the last step in a corporate transformation as the 154-year-old company shed its plastics business and remade itself as a life-science company with equally-sized health and agriculture units. Once the deal is through, three global behemoths will dominate the world’s agriculture industry, a prospect that has left farmers worried about the possibility of higher prices and less choice.

The settlement came together after Justice Department antitrust officials pressed for significant divestitures to remedy the competition problems from combining the two companies. The companies have received antitrust approval from most jurisdictions around the world. Bayer has said it’s confident the deal will close by the June 14 deadline.

Bayer initially agreed in October to sell some of its seed and chemical businesses to BASF SE for 5.9 billion euros. The deal included the Liberty herbicide brand, cotton and soybean seeds, and seed-trait and breeding capabilities.

Then in April, Leverkusen, Germany-based Bayer said it was selling more pieces of its agricultural business to BASF for as much as 1.7 billion euros to satisfy regulators. That deal covered Bayer’s vegetable-seeds business, other herbicides, research on wheat hybrids, and Bayer’s digital farming business. Those businesses had combined sales of 2.2 billion euros last year.

Last year, U.S. and EU regulators approved two other major deals in the industry, Dow Chemical Co.’s merger with DuPont Co. and China National Chemical Corp.’s takeover of Syngenta AG. With about $48 billion in sales from their combined seed and chemicals businesses, Bayer and Monsanto will surpass those of both DowDuPont Inc. and China National.