Co-chief executive Keith Skeoch said it marked the beginning of a “new chapter” for the newly created company, which is now worth £11bn ($14.3bn, €12.1bn) and has 50 offices spread across the globe with assets under management of £670bn.
The deal, first revealed in March 2017, has also created one of the largest active investment businesses in Europe, Aberdeen Standard Investments, which will manage £583bn of assets.
In a statement, the company said it would continue its “long standing” commitment to active fund management.
Skeoch, chief executive of Standard Life Investments since 2004, will continue as chief executive of the new company and said: “Our leadership team is in place and we have full business readiness from day one. Our people have worked exceptionally well together to complete the merger on schedule and we would like to thank them for this.”
Martin Gilbert, a co-founder and former chief executive of Aberdeen, will be a chief executive of the new firm.
He said: “As ever our priority remains the delivery of strong investment performance and the highest level of client service. The merger deepens and broadens our investment capabilities, and gives us a stronger and more diverse range of investment management skills as well as significant scale across asset classes and geographies.
“We believe this will enable us to deliver an even better proposition and service to our enlarged client base.”
With the confirmation of the completed merger also came news that Colin Clark, director of the global client group at Standard Life, and chief financial officer Luke Savage have both stepped down from their posts.
Clark will continue in his role until the end of August before being placed on gardening leave until the end of December 2017, and Savage will continue to work for the company until February 2018.
In a prospectus published in May, Standard Life said it expected to cut around 800 jobs over the next three years and confirmed the merged company’s headquarters would be based in Scotland.