UPDATE 4-UBS tax deal uncertain ahead of U.S. court case

* U.S. court hearing starts in Miami on July 13

* SNB chairman says expects resolution of tax conflict

* Settlement still possible, but timing uncertain

* Focus of discussions on data, not money: UBS chairman

* Shares down 2 percent (Adds additional comments, paragraphs 10-12)

By Lisa Jucca and Kim Dixon

ZURICH/WASHINGTON, July 10 (Reuters) - Swiss bank UBS (UBSN.VX) (UBS.N) braced on Friday for a high-stakes trial in the United States next week that could force it to reveal secret client data, as a last-minute deal remained elusive.

It was unclear whether wealth management giant UBS could settle the damaging tax row before a court hearing starts in Miami on Monday, weighing on its shares.

Washington is demanding that UBS disclose the identity of 52,000 American holders of Swiss accounts suspected of not paying taxes, something UBS Chief Executive Oswald Gruebel cannot comply with as it would be in breach of Swiss criminal law.

But a settlement would most likely have to include a partial disclosure of client data, possibly in an indirect way, and a non-punitive financial penalty, a second source said.

A deal could involve Switzerland agreeing to disclose some UBS client information, possibly by helping the IRS cross-check U.S. banks' data about transfers from Switzerland and UBS.

Lawyers for both sides did not return phone calls seeking comment.

Switzerland has vowed to seize UBS data to stop the bank from handing it over to U.S authorities, in an attempt to defend its crumbling bank secrecy. It said the tax case targeting its best-known bank is souring diplomatic ties and that hitting UBS hard could destabilise the global financial system.

The bank has admitted aiding U.S. clients in their efforts to hide data, as part of its criminal settlement with the Justice Department earlier this year. Many U.S. observers say the U.S. has a solid case and it is now down to diplomacy.

"The IRS has never been in such a great position," said Joann Weiner, a former economist in the U.S. Treasury Department.

"UBS has deliberately for years made efforts to get around the U.S. law; they admitted to a lot of this in the February settlement," said Weiner, who now teaches at George Washington University.