Alex Wong/Getty Images Ballooning debt will force the Federal Reserve to bring back quantitative easing, Michael Howell wrote. He said in the Financial Times that the Fed's balance sheet will have to double. "Investors should therefore expect a continuing tail wind from global liquidity instead of last year's severe headwinds." Ballooning debt in the coming years will force the Federal Reserve to buy massive amounts of bonds again, according to Michael Howell, managing director at Crossborder Capital.Writing in The Financial Times on Wednesday, he predicted that the central bank will have to abandon its quantitative tightening plan, which would roll back prior stimulus by shrinking the Fed's balance sheet.