(Bloomberg) ? AS Tallink Grupp, the largest Baltic shipping company, which started trading publicly last month, is likely to make an offer to buy Silja Line, a passenger and cargo operator with a fleet of 12 ships, to increase revenue.

?We are just making some calculations and after that we will decide,? said Keijo Mehtonen, head of the company?s Finnish operations, in an interview yesterday. ?It looks now? like ?we will give an offer,? he said.

Any offer to Silja?s owner, Sea Containers Ltd., would likely be made on January 21, 22 or 23, with the sale process taking between three months and six months, Mehtonen said.

He declined to give details of what an offer would contain and added that Tallink plans to start a service between Stockholm and the Latvian capital Riga in March.

Sea Containers, a Bermuda-based rail and shipping company that lost $58.5 million in the nine months ending in September, said on November 3 it would listen to offers for Silja and its SeaStreak ferry businesses.

It said Silja?s profit declined ?significantly? last year because of lower duty-free sales, rising fuel costs and an unsuccessful Germany-Estonia-Russia route.

Silja ?can?t run the same way as it has been for the last 20 or 30 years,? Mehtonen said. ?We can?t have such heavy organisations and marketing costs.?

Silja runs four routes: Helsinki-Stockholm, Turku, Finland- Stockholm, Helsinki-St. Petersburg and Helsinki-Tallinn. Mehtonen said a takeover by Tallink would give the company a market share of more than 50 percent on the Helsinki-Tallinn route, requiring negotiations with antitrust authorities.

Tallink shares were first traded on the Tallinn exchange on December 9. The company?s ferries and cargo ships handled more than 3.2 million passengers and about 130,000 cars, buses and trucks in the 12 months ended August 31. In May 2004, Tallink acquired a 350-room hotel in Tallinn.