Hedge funds bought up a substantial Osram stake and refused to tender their shares, speculating instead that AMS will launch a squeeze out offer at a higher price at a later point.

Osram shares closed at 44.15 euros on Monday. They were down 0.3% to 44.03 euros at 0824 GMT on Thursday.

During the final two-week extended offer period which ended on December 24, Osram's share price was trading above the 41 euros AMS offer price, leading investors sell shares on the open market rather than tendering shares to AMS.

The Austrian company needs at least 75% of Osram's shares to get access to the German company's funds to repay the debt incurred to finance the offer, which is worth about 4.6 billion euros ($5.2 billion).

AMS, known for supplying Apple with sensors for iPhones, wants to build a leader in integrated sensors and lights and develop systems for self-driving cars and smartphone applications.

AMS in December announced an initial acceptance level of 59.3%, reaching the required threshold of 55%.

($1 = 0.8922 euros)

(Reporting by Thomas Seythal in Berlin and Alexander Huebner in Munich; Editing by Edward Taylor)