'Permanent' QE theory gaining backers

Traders work on the floor of the New York Stock Exchange.
Brendan McDermid | Reuters

Brian Kelly, hedge fund manager, "Fast Money" star, and author, joined CNBC Pro in an exclusive Q&A to address investment questions from subscribers. He shares his outlook on global markets, digital currencies, commodities, and more. Watch the highlights below.

Hedge fund manager Brian Kelly believes there's a high likelihood for quantitative measures from central banks around the world to become pretty much permanent.

Since the financial crisis hit in 2008, the Federal Reserve resorted to an unprecedented measure of economic stimulus by buying immense piles of bonds, a policy known as quantitative easing.

The result, according to estimates, added $3.5 trillion to the Fed's balance sheet as the program ended last October.

Kelly isn't alone.

"With rates at zero, fiscal policy will be needed to offset any negative shock that hits global economies," Steven Englander, Citi's global head of G-10 strategy, wrote in a note to clients Wednesday."The practical way of doing so is for central banks to indicate that their balance sheets will remain large permanently and keep expanding if targets are missed, opening the door for either additional spending or lower taxes financed by the central bank."

Here's how to trade another round, and maybe permanent, QE: