(Reuters) - Biotech firm Biocon Ltd. has filed a prospectus for the initial public offering of its $600 million research services arm, Syngene, it said on Thursday.

The company plans to sell 22 million shares, including an overallotment, it said in a statement, after the prospectus was filed with India's market regulator.

It gave no value for the stock offering, but local newspaper reports said the company could raise as much as 6 billion rupees ($95 million).

In January, Biocon sold a 10 percent stake in Syngene for 3.8 billion rupees to IVF Trustee Company, valuing the group at 38 billion rupees, or just over $600 million.

Biocon had also said in January it would list Syngene by selling up to 15 percent of the unit through an initial public offer, but it had given no specific timeline.

The listing is expected to take place by July.

(Corrects to say Syngene is a research services company)