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ZURICH -(Dow Jones)- UBS AG (UBS) has stepped up its lobbying efforts for a U.S.-Swiss tax deal over confidential bank data, urging parliamentary representatives to vote for passage of the deal.

According to a document seen by Dow Jones Newswires Friday, UBS is arguing that a parliamentary no-vote could also harm other Swiss banks who offered services to wealthy Americans.

"Switzerland's refusal to honor its international obligations could send an escalating signal," UBS writes in the seven-page document, which was sent to Swiss parliamentarians this week.

UBS confirmed the contents of the document, which were first reported by Swiss daily Tages-Anzeiger.

The bank cautioned that a parliamentary no-vote in Switzerland could further raise the ire of lawmakers in the U.S., where dueling legislative proposals on tax compliance are circulating. Sen. Carl Levin, D-Mich. and representatives introduced legislation--The Stop Tax Haven Abuse Act--last year, which is aimed at ferreting out tax avoidance schemes.

"The danger is inevitable that Switzerland is seen as breaching the contract as well as designated as a tax haven, and put on a special U.S. blacklist as a result, in case the U.S.-Swiss deal doesn't pass parliament," UBS wrote.

The August 2009 agreement between the two countries is meant to settle a lawsuit brought against UBS by the U.S. Internal Revenue Service as part of a crackdown on alleged tax evasion through hidden Swiss offshore bank accounts. A key tenet of the settlement calls for Switzerland to hand over 4,450 sets of confidential UBS client data on alleged tax offenders to U.S. officials.

The parliamentary vote is the latest in the Swiss government's dwindling options on how to honor the U.S. agreement after a Swiss court effectively blocked part of the handover in January. Switzerland's parliament is expected to address the matter in June.

Company Web site: http://www.ubs.com

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