Pfizer will on Wednesday place an offer in the final round of bids for German generic drug maker Ratiopharm, a person briefed on the matter told Reuters on Wednesday.

Ratiopharm's remaining suitors, which also include Israel's Teva and smaller Icelandic peer Actavis, had been requested to make final bids on Thursday at the latest, several sources had previously said.

Officials at Pfizer were not immediately available for comment.

So far, Actavis's offer has been the highest at about €3 billion, including assumed debt, sources have said.

This would make the deal the biggest generics takeover since Teva's $7.5 billion purchase of U.S. rival Barr, announced in July 2008.

Industrial heir Ludwig Merckle put Ratiopharm on the auction block as part of concessions made to creditors by his father Adolf Merckle who committed suicide in January 2009 after ceding control of his business empire to lenders during the financial crisis.

Earlier this month Pfizer pledged to invest in growth as it sought to win Ratiopharm, a week after Teva outlined its plans, people familiar with the situation said.

Indebted Icelandic generic drugs maker Actavis, for its part, has raised the prospect of taking the enlarged company public should it win the auction, people familiar with the sale process have said.