He warns that advisers need to ensure that in a period of volatility they have true diversification and not take accidental stock concentration.
Over the past 10 years he explains that the focus in multi-asset investing has been more about chasing returns and less about managing risk, a trend that he cautions against.
For example, he points at the growth in stocks such as Microsoft, Amazon, Google and Alphabet, which have been a large driver in the overall performance of the total global equity benchmark.
The four technology stocks now have much larger market capitalisations, and between them they account for a bigger percentage of the MSCI index than the UK.
Mr Onuekwusi says: “It is really important as we move into this period of volatility that the focus turns back to diversification and risk management.
“The danger is if we just focus on returns and not what is in the portfolio, you simply might not be getting that diversification.”
Ima Jackson-Obot is deputy features editor of Financial Adviser and FTAdviser.com