FRANKFURT (Reuters) – Swiss contract drug maker Lonza has shortlisted German chemicals group Lanxess and private equity groups in the sale of its Lonza Specialty Ingredients (LSI) unit worth more than 3 billion Swiss francs ($3.38 billion), people close to the matter said.

Buyout groups Advent, Carlyle, Partners and a consortium comprising Bain and Cinven were among those advancing to the next round of bidding, which will be followed by one final one round, they said.

A total of six were allowed to proceed, the two people said, adding that it was unclear whether another private equity firm or another industrial player had made it through. Lone Star private equity and SK Innovation have been mentioned as possible bidders.

LSI has annual earnings before interest, tax, depreciation and amortisation of about 300 million Swiss Francs ($323 million) and may be valued at 10-12 times that in a potential deal.

The Basel-based company, which announced the sale plans in July, declined to comment, as did the suitors.

LSI is divided into two units, one making microbial controls for paints, hygiene, personal care and wood treatment, and a specialty chemicals services business offering contract manufacturing to clients.

The company is among several Swiss industrial groups that are shedding non-core assets to simplify corporate structures.

Last month, engineering group ABB said it planned to offload three of its most profitable businesses – turbocharging, mechanical power and power conversion divisions – to focus on fewer business areas to improve it margins and sales.

Separately, chemicals group Clariant has put its pigments business up for sale and has shortlisted private equity firms, including Triton and Lone Star, people familiar with that deal said.

Clariant, Triton and Lone Star declined to comment.

($1 = 0.8885 Swiss francs)