Bayer’s plan to acquire Monsanto is likely to spur US regulators to demand the sale of some cotton seed assets to alleviate concerns that the $66 billion deal could hurt competition in one of the country’s largest row crops. The deal also faces conglomerate antitrust issues. Cotton seed, canola seed and glufosinate herbicide assets, with sales totaling about $1.2 billion, may need to be divested.

Monsanto became the largest US cotton seed company in 2007. To satisfy antitrust concerns, Monsanto agreed at the time to sell its Stoneville Pedigree Seed unit, which had 12 per cent of US cotton seed sales, to Bayer for $310 million. It also agreed to divest its smaller NexGen cotton seed brand. After those asset sales, Monsanto had 51 per cent of US cotton seed sales and Bayer 41 per cent.

This year, Monsanto’s Deltapine brand had 33 per cent of the market, an increase of two percentage points from last year. Cotton seed generated $523 million of sales at Monsanto last year, about 3.5 per cent of the company’s total revenue. Bayer had 1.27 billion euros of seed sales in 2015. Monsanto’s seed sales totaled $10.2 billion.