While the Federal Reserve is gradually raising interest rates in the U.S., the actions by two other central banks are actually the most important thing to watch right now, bond guru Bill Gross told CNBC on Wednesday.
And it is something that could possibly wreak havoc on the bond market, he said.
That is because monetary policy in both Europe and Japan is causing international investors to buy U.S. Treasuries, he explained.
The European Central Bank is currently buying 80 billion euros ($85.7 billion) a month in bonds and Japan's 10-year is pinned at zero to 10 basis points, said Gross, who runs the Janus Global Unconstrained Bond Fund.
"Once [ECB President Mario] Draghi begins to taper, that probably won't happen for a few months, but once he begins to taper and reduce that $80 billion a month, once that zero to 10 basis point cap is eliminated in Japan, then hell could break loose in terms of the bond market on a global basis," he told "Power Lunch."
Stocks and bonds were both up on Wednesday after the Fed announced it was raising interest rates by 0.25 point, bringing the overnight funds rate to a target rate of 0.75 percent to 1 percent.
Gross believes the markets are rallying because the Fed's statement was a little less hawkish than some had feared.
In fact, he thinks Fed Chair Janet Yellen is a dove at heart.
"She critically fears that markets, that asset prices are subject to downturns and in some cases significant downturns – not black swans, but maybe gray swans – and so she wants to move on a gradual basis and indicate that to the marketplace," he said.
And Gross does not expect too much change in tone when President Donald Trump begins to make appointments to the central bank.
"There's a tendency always for presidents to select dovish chairman and dovish policy members in order to perpetuate the economic cycle for the next election," he said.
"We're going to have to watch the appointments but I would anticipate more doves than hawks as we move along in the next 12 months."
Yellen's term as chair expires at the end of January 2018.