FRANKFURT (Reuters) – U.S. life science tools company Thermo Fisher on Monday launched its agreed $11.5 billion takeover offer for Qiagen, calling on investors of the German genetic testing specialist to tender their shares.

Thermo Fisher said in a statement that the period for acceptance of the offer was scheduled to end on July 27 at 2200 GMT.

Qiagen shares have traded near or above the offer price of 39 euros this month on speculation the bidder might sweeten its offer.

Qiagen’s management, in turn, reaffirmed its backing of the transaction in a detailed “Reasoned Position Statement” on Monday.

The shares were up 0.9% at 39.41 euros at 0925 GMT.

(Reporting by Ludwig Burger; Editing by Michelle Martin)