Investment managers Standard Life and Aberdeen have agreed an £11 billion pound all-share merger.
The combined firm will manage assets worth £660bn and employ about 9,000 people.
Speaking on BBC radio, Aberdeen Chief Executive Martin Gilbert said the deal would lead to job losses where the two firms had an overlap, although it was too early to say how many would go.
Gilbert would share the top job with Standard Life Chief Executive Keith Skeoch.
As an all-share merger Aberdeen shareholders will own about a third of the combined group, with Standard Life shareholders owning the remaining two thirds reflecting Aberdeen’s £3.8bn market capitalisation and Standard Life’s £7.5bn value.