The probe was announced this afternoon by the CMA.
The CMA published a notice, which stated: “The Competition and Markets Authority is considering whether it is or may be the case that this transaction, if carried into effect, will result in the creation of a relevant merger situation under the merger provisions of the Enterprise Act 2002 and, if so, whether the creation of that situation may be expected to result in a substantial lessening of competition within any market or markets in the United Kingdom for goods or services.”
The deadline for the CMA to announce its decision whether to refer the Merger for a Phase 2 investigation is 18 July.
An invitation to comment closes on 6 June.
Standard Life released a statement to the Stock Exchange in response to the CMA announcement, saying it had today filed an application with the CMA in respect of the proposed merger.
The firm stated: "This has triggered today's announcement by the CMA that the standard phase 1 review of this application is now underway.
"This is one of a number of regulatory and antitrust approvals being sought as part of the merger process. Approval for the merger has already been granted by competition authorities in the US and Germany."
In recent weeks, it was revealed that eight hundred jobs are to be lost as a result of the merger.
The companies also revealed details on branding, saying Standard Life will be renamed Standard Life Aberdeen.
A statement about the future of the firms released earlier this month read: “Synergies will come in part from employee departures arising from natural turnover. Other appropriate steps will be taken to minimise the number of compulsory redundancies, including the active management of Standard Life’s and Aberdeen’s recruitment and vacancies.”
The companies stated in a report that they “expect to achieve cost synergies” where they find ‘duplication’.
Standard Life and Aberdeen announced the deal in March.
The combined group will include, and operate under, branding drawn from both firms.
The combined group is likely to be reorganised to bring the investment businesses of the Aberdeen Group and the Standard Life Group together in a single investment sub-group – to be named or Renamed Aberdeen Standard Life Investments.
The report stated that the global brand strategy for the combined group is “currently being developed and will reflect appropriate positioning for all businesses within the group, including the investment business”.
The plan is that it will be headquartered in Scotland and continue to have offices around the world.