ST. LOUIS, Mo. — Swiss agribusiness giant Syngenta AG continues to ignore attempts by the Monsanto Co.’s push for a $45 billion takeover bid despite proposing a surprise whopping $2 billion breakup fee if the two companies did merge but regulators tossed the deal out, and Monsanto says it would sweeten the deal if the European company did agreed to talks.

As Monsanto officials meet in Europe to convince their international investors of the deal, new details have emerged disclosing the company’s desire to establish a new headquarters in London if the cash and stock acquisition was approved. The revelation was included in a letter sent to Syngenta by Monsanto CEO Hugh Grant.

Such a move to Great Britain would cost U.S. taxpayers up to $500 million in lost U.S. tax revenue and spur intense review by U.S. antitrust regulators, according to an analysis by The Wall Street Journal.

On the home front, the world’s largest supplier of crop seeds is preparing to head off a possible re-vote by American famers with plans to meet with farmers across the country in coming weeks, in an attempt to win support from nation’s 2.2 million farm producers. Already the National Farmers Union has said it is skeptical of the deal, while the American Farm Bureau Foundation is taking a "wait and see" position, according to Will Rodger, its director of Policy Communications.

Attempts to reach Monsanto for details of the planned meeting with farmers was fruitless. Voice messages left with Monsanto spokesperson Sara Miller were not returned by press time.

Following the latest Syngenta rejection, Grant fired off a letter to its board of directors on June 6, saying Monsanto would consider sweetening its May offer of $477.87 per share if Syngenta would sit down for talks and open its financial books. Forty-five percent of Monsanto’s offer would be in cash, the rest in stock.

Syngenta Chair Michael Demare and Chief Executive Mike Mack wrote in a letter early last week to its shareholders: "Monsanto’s second letter represents the same inadequate price, same inadequate regulatory undertakings to close, same regulatory risks and same issues associated with dual headquarters’ moves."

Syngenta said Monsanto’s plans included renaming the company and locating its new headquarters in the United Kingdom, a move that would lower the tax rate of the combined companies. Any changes in the U.S. tax status, however, would likely meet harsh objections by Congress – Monsanto’s U.S. tax rate is about 29 percent, while Syngenta enjoys a lower rate in Switzerland at nearly 15 percent.

Fearful of a deal that would cost the United States so much in lost tax revenue, U.S. Sen. Richard Durbin (D-Ill.) has called on Congress to pass legislation that would make it more difficult for companies to incorporate abroad to avoid taxes.

Also in the June 6 rejection letter, Syngenta’s executives said Monsanto’s plans to divest all of Syngenta’s seed business and those pesticides that compete with Monsanto’s still face an antitrust huddle that regulators surely won’t miss.

To get a deal speculators surmise Monsanto will be forced to raise the value of its $45 billion cash and stock proposal, and may have pitched the plan at its stockholders meeting in Europe. Grant previously wrote that the $45 billion deal represented a compelling value to Syngenta at a 43 percent premium to its share price prior to news of the dual talks last April.

With Monsanto’s latest offer of a $2 billion breakup fee, Grant said in his letter to Syngenta, "We’ve backed our confidence by agreeing to divest overlapping businesses, and offered a $2 billion reverse breakup deal to further demonstrate our commitment to this combination."

Based in St. Louis, Monsanto manufactures seeds and chemicals used in crop protection, including insecticides. The company has more than 21,000 employees in 66 countries and $15.9 billion in sales. Syngenta, based in Basel, Switzerland, produces insecticides, fungicides, herbicides and seeds with total sales of $15.1 billion last year and employs 28,000 workers in more than 90 countries. Syngenta is the world’s biggest seller of agricultural chemicals and is ranked third in seed sales.