The country's national anti-corruption agency, USKOK, said there was no evidence linking Polancec to the deal.
Longtime former Prime Minister Ivo Sanader is being investigated on charges that he abused his position in the sale of Croatian energy firm INA to Hungarian oil giant MOL, for which he allegedly received a €10 million bribe. Prosecutors say he accepted the money from MOL chief executive Zsolt Hernadi in exchange for management rights to INA that were higher than MOL was entitled to by its ownership share.
The Hungarian firm, which owns 47.25 percent of INA, denies making any illegal payments. The Croatian government owns 44.8 percent and the remainder is privately held.
Hungarian authorities told Bloomberg that they are also investigating potential graft, but have yet to name a suspect.
Although Polancec has been cleared in this case, both he and his former boss are implicated in other high profile corruption cases. The former deputy is currently being tried with seven other people for embezzling €50 million from Podravka, one of Croatia's largest food companies.
Sanader was also indicted in August for accepting almost $700,000 in bribes from Austria’s Hypo Alpe-Adria-Bank International AG in return for facilitating almost $15 million in loans to Croatia.
