UBS threatens to move HQ from Switzerland -paper

* UBS reported to object to holding company idea

* Proposal part of "too big to fail" debate

* Foreign subsidiaries would require expensive capital

GENEVA, Nov 29 (Reuters) - Swiss bank UBS (UBSN.VX) is threatening to move its headquarters out of Switzerland if the authorities impose too many new regulations in the wake of the global financial crisis, Swiss weekly paper Sonntag CH said.

Oswald Gruebel, chief executive of Switzerland's biggest bank by assets, made the threat in a speech to businessmen last week, citing the possibility that the authorities would force major banks to reorganise as holding companies, the paper said on Sunday.

A UBS spokeswoman declined to comment on the report.

Gruebel spoke to the Zurich Business Club on Thursday at a closed-door event at which reporters were not present.

The idea of forcing banks in Switzerland to operate as holding companies is part of the discussion on supervising banks deemed "too big to fail".