The plot surrounding the proposed merger of Dow and DuPont continues to thicken.

After the companies late last week signaled that the deal could take longer due to regulatory inquiries, rumors quickly resurfaced that heavyweight BASF was and possibly still is interested in sticking its foot into the door.

International media reports say BASF has sought advice from financial advisers – some of them named Deutsche Bank and Citgroup – on how best to launch a counter bid for Syngenta.

It is unclear whether this meant the German group was hoping to outbid Monsanto or ChemChina, the buyer that eventually won the race. Earlier reports that said BASF was weighing a joint bid with Monsanto, would point to the latter.

In a regulatory filing with the US Securities and Exchange Commission (SEC) at the beginning of this month, DuPont said it had discussed a full or partial merger with several unidentified companies before sealing a deal with US rival Dow last December.

Despite the “big and bigger” rumours – BASF is world’s largest chemical producer by sales – most observers believe, that at this point, the German group may be only looking to acquire some of the assets Dow or DuPont would have to divest to appease antitrust authorities.

Only a complete merger with DuPont would give BASF access to the seeds portfolio some analysts think it could be seeking. Speaking against this theory are recent remarks by CEO Kurt Bock that it is happy to concentrate on seed traits and leave product development and marketing to Monsanto, with which it has a cooperation agreement.

If one of the parties to the Dow-DuPont merger breaks the deal it could be liable for a termination fee of $1.9 billion.