Zurich  - The Swiss bank UBS said Thursday it has made a tender offer worth up to 1 billion euros (1.34 billion dollars) to buy back bonds in an attempt to raise its Tier 1 regulatory capital ratio.

The offer pertains to four lower tier 2 bonds with maturity dates between November 2015 and September 2019 and a notional value of around 7 billion Swiss francs (6.15 billion dollars).

The bank said in a statement that the bonds were currently trading at a significant discount to their original issuance price.

Tier 1 capital ratio is a regulatory measure of a bank's financial stamina.

UBS, in a separate statement said it would ask shareholders at an upcoming meeting next month to approve the creation of authorized capital, as a contingency measure.

They would also be asked to approve the creation of conditional capital related to UBS's deal with the Swiss National Bank, as part of a bailout plan agreed on last year. (dpa)