Italy's highest court has upheld a ruling that Silvio Berlusconi's family investment company must pay a huge fine for corruption, but gave it a slight discount on the half a billion euro judgment.

The Court of Cassation on Tuesday rejected most of Fininvest's objections to lower courts' rulings against it for corruption in the purchase of the Mondadori publishing house, a key step in the creation of Berlusconi's media empire in the 1990s.

An appeals court had awarded a rival media company 564 million euros — down from an initial 750 million euros. But the high court lowered damages to 541 million euros ($722 million).

Berlusconi is fighting efforts in the Senate to remove him from office after his tax fraud conviction, threatening the stability of Italy's uneasy coalition government.