(Updates stake and acceptances)
VIENNA, Oct 1 (Reuters) - Austrian sensor specialist AMS had secured around 30% of Osram shares shortly before its takeover offer is due to expire at midnight on Tuesday, and it may take days before it knows whether it has reached the 62.5% threshold.
AMS is engaged in a bidding war with a private equity consortium for the German lighting group and said on Tuesday it had secured a direct holding of 19.99% in Osram shares plus 9.16% of the stock that had been tendered by Monday night.
However, it could take several days to determine the total number of shares tendered to the Austrian company by the Tuesday night deadline, partly because institutional investors traditionally sell their stock at the last minute. Many do so via depositary banks, which could cause an additional delay.
AMS upped its bid to 4.5 billion euros ($4.9 billion) last week after private equity group Bain Capital signalled it could team up with U.S. firm Advent to beat AMS's initial offer of 4.3 billion euros. Bain and Advent have made no further move so far.
Bain, together with Carlyle Group, offered 4 billion euros for Osram, a leader in automotive lighting. Bain turned to Advent after AMS entered the ring and Carlyle was not ready to add more funds, sources have said.
Swiss-listed AMS, which is best known for supplying Apple with sensors for iPhones, wants to expand in the auto industry and supply manufacturers with sensors and lighting systems for self-driving cars to reduce its dependence on smartphone producers.
If AMS fails with its offer, it cannot launch a new bid for 12 months, unless Osram and the German regulator give their approval. AMS's shareholding could make it more difficult for other interested parties to take over Osram.
Allianz Global Investors, which holds 9.4% of Osram shares, signalled weeks ago that it might sell them to AMS.
As there is a public holiday in Germany on Thursday, there is a chance the result will not be announced before Friday.
$1 = 0.9173 euros Reporting by Kirsti Knolle; Additional reporting by Alexander Huebner; Editing by Pravin Char and Mark Potter