The posts will be cut over three years during restructuring after the £11bn merger of Standard Life and Aberdeen Asset Management.
The two companies currently have  a combined worldwide workforce of approximately 9,000 people.
The information is contained in a detailed prospectus published by Standard Life on the deal.
Managers said they expected "natural turnover" to account for some of the reductions, while other steps will be taken to minimise compulsory redundancies.
The merger of Edinburgh-based Standard Life and Aberdeen is aimed at creating cost savings that could add up to £200m per year.
The prospectus for shareholders stated "there will be a need to maximise operational efficiencies and cost synergies" to achieve the expected benefits of the merger.
It continued: "At this time it is estimated that the integration and restructuring will result in a phased reduction of approximately 800 roles from the total global headcount of the combined group as at 31 December 2016 of approximately 9,000 over the three-year integration period.
"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 document reveals that the newly-merged company will be renamed Standard Life Aberdeen plc.
Both companies have agreed on a 16-strong board made up of an equal number of Standard Life and Aberdeen directors.
Standard Life chairman Sir Gerry Grimstone will be the chairman of the newly-merged company while Aberdeen's chairman Simon Troughton will become deputy chairman.
Keith Skeoch, the Standard Life chief executive, and Aberdeen boss Martin Gilbert will become co-chief executives of the new firm.
The two companies agreed the terms of the merger, which will create Britain's biggest asset manager, in March.
Under the terms of the deal, Aberdeen shareholders would own 33.3% and Standard Life shareholders would own 66.7% of the combined group.
A general meeting has been scheduled for June at which shareholders will be asked to approve the merger. If backed, the deal is expected to be closed by mid-August.
About 800 jobs are to be cut in a planned merger of two of Scotland's biggest financial companies.