Switzerland's biggest bank, UBS, should complete its merger with the United States investment bank, PaineWebber next Friday.
PaineWebber shareholders now have until 5 o'clock New York time on Wednesday next week to decide whether they want to swap their stock for cash or shares in UBS.
PaineWebber shareholders approved the merger earlier this week.
However, it's still subject to the approval of the regulatory authorities.
swissinfo with agencies