Nearly 70% of discretionary fund managers (DFMs) rate Brexit as the biggest risk to their investment portfolios, according to a survey conducted by CoreData Research.
A study of 92 DFMs carried out in August found seven out of 10 asset allocators believe Brexit poses the biggest threat to their investments.
Meanwhile, two thirds also believe Britain's decision to leave the EU in June does not improve the outlook for UK equities in the long term.
However, just 37% of those surveyed said they would consider reducing their exposure to UK equities prior to the triggering of Article 50, which Prime Minister Theresa May said would happen by the end of March 2017.
The study, which asked DFMs to select the three biggest factors that could negatively impact their investments, also found 55% were concerned about weak global GDP growth, while 52% highlighted geopolitical instability could threaten their positions.
As a result of these concerns, more than eight out of 10 DFMs said they will prioritise risk management within client portfolios over the next 12 months, while 70% of wealth managers said international equities will emerge as the strongest performing asset class in the next year.
Just 16% of respondents said UK equities will be the best performing asset class post-Brexit, while only 8% expect alternatives to outperform, and just 3% were bullish on property and fixed income.
Meanwhile, more than 80% said the chase for yield is the biggest challenge currently facing DFMs, while 83% said active management is essential in the current market environment.
"The UK's decision to exit the European Union, combined with a number of economic headwinds, could hit growth hard over the next 12 months," said Craig Phillips, head of international at CoreData Research.
"DFMs acknowledge this and say they are prioritising risk over return as they look to manage clients' assets across choppy waters."
Aim must be preservation of capital
Targeting £10,000 for ATLAS Foundation
Unwinding EU membership is unprecedented
Highlights of group's 2017 Analyst Survey
Takes immediate effect