Merlis will manage both discretionary and advisory accounts for onshore and offshore clients and will be based in London.
He will work alongside Guatam Batra, chief investment officer of Signia Wealth.
Previously Merlis worked at JPMorgan Private Bank, fulfilling a similar role for clients based in Europe and the Middle East.
Before that he was a derivatives marketer to French and Benelux financial institutions for Citibank.
Nathalie Dauriac-Stoebe, CEO of Signia Wealth, said: "Etienne has an exceptional track record in managing ultra high net worth client accounts and our investment team will benefit greatly from the added experience that he brings.
"Signia Wealth has very quickly assembled a hugely experienced and skilled investment team and expects to continue its rapid growth."
Since its launch in March 2010 Signia Wealth has ammassed £2bn in assets under management.
