Some investors say the Fed's decision to hold off on rising has increased market uncertainty, but Marks said "investors have to know that it's their job to bear uncertainty."
His advice for investors: Have a balance of offensive and defensive assents in your portfolio and favor caution.
Similarly, Karissa McDonough, a fixed-income strategist at People's United Bank, is telling her clients to reposition their fixed-income portfolios and to scale back on risk. With its involvement in the markets, the Fed has, effectively, set a floor on valuations, but that put will soon go away, and investors — especially those investing in fixed-income assets — should prepare for that to happen soon, according to McDonough.
When the Fed does decide to lift off, "we're going to go back to historical volatility level and returns are going to be compressed," McDonough said.
"In this environment, the Fed is affording us an opportunity with this delayed hike cycle to reposition portfolios and to exit or reduce exposure to riskier asset classes," McDonough said.
"This is certainly not the time to bottom fish; this is a time to upgrade the quality, even within the risky high-yield space."