As the board of UBS AG begins a three-day meeting Wednesday, the stakes are high for chief executive Oswald Grübel, who is likely to present directors with the first sketch of how he proposes to accelerate a planned shrinking of the investment bank as a result of last week's rogue trader scandal.

The board may also discuss whether to renew its confidence in Grübel's leadership or await the outcome of the Swiss bank's internal investigation into the scandal before deciding whether to make high-level management changes, according to a person familiar with the situation.