The former chief executive of the Balmain Aqua trusts, Stephen Tunley, would assume management responsibility for the Balmain MMT Mortgage Trust FT18 Units and FT36 Units, S&P said in a statement.
"Despite our familiarity with Mr Tunley and the funds' continued access to Balmain's large in-house lending capability, we believe that the departure of Mr Thomas is material," S&P analyst Nathan Bode said.
"Mr Thomas has played a critical role in managing and promoting the fund and, as such, we believe a fund review is warranted."
S&P would meet with Balmain Funds in the short term to resolve it's on hold revision, Bode said.
The funds were rated three stars.