The departures were viewed by one senior industry observer as marking the start of a significant cost-cutting programme.
Believing it was likely there would be sizeable staff cuts in the enlarged group as a result of Aberdeen's takeover of SWIP, the observer said: "You replace the people at the top, and then you know what is coming after that."
However, Aberdeen Asset Management (AAM) appeared keen to play down the scope for further cuts, declaring there was "not significant overlap" between the two businesses.
Senior SWIP fund management executives Lynda Shillaw, director of real estate, Mark Connolly, director of fixed income, and Will Low, director of global equities, are those who are leaving with Mr Buckley as a result of a top level reorganisation by AAM.
A spokesman for AAM declined to comment, when asked whether the four executives who were departing would receive pay-offs.
An industry source said: "In these kind of things there is usually a redundancy kind of thing, or pay-off. You can imagine them all receiving some compensation."
It would seem likely the total amount of the pay-offs to the four senior executives could run into millions of pounds. The accounts show that the highest paid director of SWIP received £1.45 million of emoluments in 2013.
AAM did not specify the departure dates of the four who are leaving. However, the industry source thought it likely they would depart within the next few weeks.
Martin Gilbert, chief executive of AAM, said: "Dean, Lynda, Mark and Will all made significant contributions to the SWIP business and helped ensure it was in the best possible shape as the acquisition completed. I would like to thank them for their professionalism throughout this process and wish them all the very best for the future."
AAM said on April 1 that it had completed its £550m acquisition of SWIP from Lloyds.
It noted then that the deal would create an enlarged group with funds under management of about £324.5 billion, based on figures at February 28. SWIP had assets under management of £138bn at February 28, with Aberdeen's total coming in at £186.5bn.
The spokesman for AAM yesterday noted its workforce had been more than 2,000 before the SWIP deal. Edinburgh-based SWIP employs more than 400 people.
Asked whether Aberdeen had any plans for more widespread cuts in staff in the wake of the takeover of SWIP, the spokesman replied: "Our focus is on the enlarged group's potential growth. SWIP brings with it new products, good people and different skill-sets. For us, two plus two equals five, not three. There is not significant overlap between the two."
This statement, while seeming to play down potential for staff cuts, appears to stop short of ruling out reductions in personnel.
AAM said, as part of the restructuring in the wake of the SWIP deal, its "alternatives" business would become a standalone unit under the continued leadership of Andrew McCaffery.
Mr McCaffery, who joined AAM in 2006, is responsible for alternative investment products globally, including hedge funds as well as private equity, infrastructure and property multi-manager funds.
AAM said its Aberdeen Solutions business, which offers a range of investment strategies spanning multiple asset classes and risk profiles, would be led by Archie Struthers, previously managing director of investment solutions at SWIP.
It added that a new quantitative investments unit, focusing predominantly on "passive" equity portfolios or tracker funds, had been created under the leadership of Sean Phayre. Mr Phayre was formerly director of quantitative investments at SWIP.
Mr McCaffery, Mr Struthers and Mr Phayre will be members of AAM's group management board.
AAM said that its three other investment businesses, active equities, fixed income and property, would continue to be led by Hugh Young, Brad Crombie and Pertti Vanhanen respectively. Mandy Pike, AAM's global head of dealing, has also joined the group management board.