VIENNA, April 9 (Reuters) - Austrian property investor Rene Benko has raised his stake in real estate group S Immo to 29.1 percent of voting rights, just shy of the 30 percent threshold that requires a mandatory takeover offer, S Immo said on Monday.
Benko bought a 7.3 percent stake from insurance company VIG , S Immo said, without disclosing a purchase price.
Benko's move comes weeks after U.S. private equity firm Starwood offered to acquire stakes in S Immo's rivals CA Immo and Immofinanz.
S Immo holds stakes in both companies.
Immofinanz and CA Immo hold stakes in each other. The two companies abandoned merger plans last month.
Analysts and industry experts have said that a combination of Austria's three remaining listed property groups would make sense.
It would speed up a shift of power in the central and eastern European sector after Vonovia became Germany's biggest residential property group by taking over its Austrian counterparts Buwog and Conwert.
Board members of S Immo, Immofinanz and CA Immo have said in recent weeks that consolidation in the real estate sector would make sense and that size was an important factor in gaining access to financing.
Benko, who according to his website owns a real estate portfolio with a gross asset value of more than 10 billion euros ($12.32 billion) via his Signa Holding, was not available for comment.
S Immo's 1.8 billion euro portfolio comprises offices and shops in Austria, Germany and eastern Europe. CA Immo's and Immofinanz's portfolios are each twice the size in value but comparable in geographical focus. ($1 = 0.8119 euros) (Reporting by Kirsti Knolle. Editing by Jane Merriman and Adrian Croft)