Probe into Julius Baer Data Theft Started

-- Swiss-German tax treaty caught up in domestic politics

-- German opposition opposes treaty, Swiss may call referendum

-- Swiss banks face uncertainty, costs

ZURICH--Swiss prosecutors Thursday said they opened an investigation into the theft of data from Swiss bank Julius Baer that German authorities allegedly bought amid a drive to crack down on suspected tax evaders.

Tensions between Switzerland and Germany are already rising ahead of a key vote in German parliament to ratify a treaty between the two countries aimed at drawing a line under past allegations that Swiss banks assisted tax evasion and at mapping out a future path.

Signed by the two governments a year ago, the treaty has been caught up ever since in domestic politics. Germany's opposition Social Democrats consider it too soft on tax evaders and threatened to bring the proposed deal to the upper house of parliament, where they hold a majority.

Even though the treaty--and similar deals with the U.K. and Austria--was approved by the Swiss parliament in May, it also faces opposition here and may be contested in a referendum. The British and Austrian deals could also be in jeopardy if opposition intensifies.

For Swiss banks, this creates uncertainty and costs, because they must move ahead with investments to implement the deal, but risk having to write those expenditures off if the deal falls apart.

Under the proposed agreement, Germans with hidden accounts in Switzerland would pay a withholding tax to their home country each year and be charged a punitive retroactive tax on undeclared capital to regularize the past. In exchange, the Swiss won't turn their names over to Berlin.

Germany's government still favors the deal, and recently said it expects to collect around 10 billion euros ($12.6 billion) in retroactive taxes from it. In Switzerland, banks and governments back the deal because it allows them to draw a line under the past and accept only declared assets going forward, while preserving its precious bank-secrecy laws.

But the deal's planned implementation on Jan. 1 has become increasingly uncertain in recent weeks after several opposition-led states in Germany said the won't support it in a parliamentary vote later this year.

The debate has became more heated since German media reported that data containing details on clients of Julius Baer was allegedly sold to the German state of North-Rhine Westphalia, which is one of the fiercest opponents of the tax deal.

The office of Switzerland's attorney general Thursday said a suspect has been arrested in connection with the alleged data theft, but declined to provide additional information.

Julius Baer said it wasn't in a position to comment on ongoing legal proceedings. But Chief Executive Boris Collardi confirmed in a recent interview with Swiss weekly SonntagsZeitung that the bank had fallen victim to data theft.

Last year, Julius Baer agreed to pay German authorities EUR50 million to end an investigation over undeclared client assets in a separate case of data theft, while Credit Suisse paid more than EUR150 million to settle a case looking into hidden assets held by German clients.

"It would of course be annoying, if the agreement didn't come into force," said Anne Cesard, a spokeswoman for the Swiss finance ministry. Swiss banks could still go ahead with their strategy of no longer accepting undeclared assets going forward, but they wouldn't be able to fully shed their reputation of helping tax dodgers, Ms. Cesard said.

It would also be costly. The Swiss Banking Association estimates that investments into information technology, processes and personnel to implement the treaties amount to around 500 million Swiss francs ($523.2 million). Especially for smaller banks, the costs are substantial, even more so considering that profits are already suffering because clients are reluctant to hold anything but cash in today's difficult financial markets.

The U.K. and Austrian governments have already ratified similar treaties with Switzerland. But they may yet be subject to a Swiss referendum, if opponents of the deal manage to collect sufficient signatures to call a national vote ahead of a Sept. 27 deadline.

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