Two European banking powerhouses have become embroiled in a €35bn (£30bn) takeover battle after Italy’s UniCredit stepped up its long-running pursuit of German lender Commerzbank, despite strong opposition from the German government.

UniCredit first took a stake of 9% in Commerzbank in September 2024 and has since built up its holding to just under 30%. It said on Monday it was pushing to increase that holding further and push the rival lender into formal merger talks.

Under German law, a shareholder that has a more than 30% stake is required to make a takeover bid. The Milan-headquartered bank said on Monday it was planning a share swap that would imply a €30.8 price per Commerzbank share, or about €34.7bn in total. Commerzbank’s share price rose to €31.30 on Monday in early trading.

The move puts it on a collision course with Commerzbank’s board and the German state, which bailed the bank out during the 2008 financial crisis and still has a more than 12% holding.

“UniCredit signals openness for ​dialogue and willingness to build bridges with Commerzbank and key stakeholders,” Unicredit said.

UniCredit said the offer would push it beyond the “30% cliff edge that exists under German takeover law and foster constructive engagement with Commerzbank and its stakeholders in the coming weeks”.

It added: “The board of UniCredit regards this offer as a sensible, pragmatic measure with no downside, given that the existing stake continues to be significantly value-accretive irrespective of the offer.”

Frankfurt-based Commerzbank is one of the oldest banks in Germany, founded in 1870. It has about 40,000 employees across 40 countries.

The 2008 bailout involved the German government injecting €18.2bn of cash.

“The German government’s position on this is well known and remains unchanged in all respects,” a spokesperson for the German finance ministry said, according to newspaper Die Welt. “We are committed to Commerzbank’s independence.”

The former German chancellor Olaf Scholz has also called the Italian move “an unfriendly attack”.

UniCredit is Italy’s second largest lender, and has returned to profitability after the global financial crisis. It now owns another German bank, HypoVereinsbank.

Commerzbank, meanwhile, is one of the biggest lenders to the Mittelstand – the small and medium-sized family-owned businesses that form the backbone of the German economy. However, it has come under repeated takeover attempts, including a collapsed merger deal with Deutsche Bank.

“This move is not coordinated with us,” said Bettina Orlopp, Commerzbank’s chief executive,adding that the offer “does in fact not include a premium for our shareholders”.

Verdi, Germany’s second-largest trade union, has also repeatedly opposed a potential takeover by UniCredit. “We reject a takeover in view of the impact on the German economy and especially on jobs in Germany at both institutions – HypoVereinsbank and Commerzbank,” said Christoph Schmitz-Dethlefsen, a union board member, on Monday.

UniCredit said it expects to launch the offer formally at the beginning of May, after a shareholder meeting where it will seek to gain investor approval for the move.

Other leading investors in Commerzbank include BlackRock, with just under 6%, and Norway’s sovereign wealth fund, which holds about 3%.