Italy’s UniCredit moved to buy another big chunk of Commerzbank, shrugging off German opposition to a possible takeover and upping the ante in its attempt to create a European banking champion with nearly $1.

Italy's UniCredit defied Germany's defence of Commerzbank by using derivative contracts on Monday to raise its potential stake in the German bank close to 21%, while waiting for regulatory approval to go above 9.

Tensions between Germany and UniCredit SpA burst into the open Monday as the government said it opposes a takeover of Commerzbank AG while the Italian lender moved to raise its stake.Most Read from BloombergThe Moonshot Plan to Eliminate Deaths on America’s RoadsUnlocking the Hidden Power of Zoning,