Billionaire money manager Jeffrey Gundlach warned that Wall Street might not be ready just yet for a Bernie Sanders presidency.

Gundlach said Sanders seems to be the most likely to secure the Democratic nomination for president. But he said the biggest risk of 2020 is Sanders “becoming more believed in.”

“The financial markets broadly will have to deal with the fact that there could be a scare that Bernie Sanders is starting to become a plausible candidate for the nomination,”  Gundlach said Tuesday on his annual “Just Markets” webcast.

Meanwhile, Gundlach also said his strongest market conviction is that the still-resilient dollar will weaken.

The greenback has largely defied expectations for its demise, with the Bloomberg Dollar Spot Index ending last year less than 1% lower as foreign-exchange volatility dwindled.

But the DoubleLine Capital chief executive officer said growing U.S. government and trade deficits, a steepening yield curve and a pull-back in foreign investment may finally hit the currency.

“My highest conviction idea is that the dollar will weaken,” Gundlach said. “As foreigners start to divest from the United States, which I think is going to be a theme of the next few years -- it may start this year -- you’ll start to see a much weaker dollar.”

Gundlach, whose Los Angeles-based fund company oversees almost $150 billion in assets, has been warning of a potential dollar slide since at least early January 2018. Should that decline materialize, Gundlach expects it to benefit gold and other commodity prices.

The money manager said he doesn’t expect broad stock and bond market returns this year to “come anywhere close to 2019,” when virtually all major assets delivered once-a-decade performances. However, investors can expect higher volatility in the decade ahead, according to Gundlach.

“It won’t be the roaring ’20s and it won’t be the boring ’20s,” he said.

Other takeaways from the webcast:

• The bond manager said forward indicators are “flashing yellow” for recession. He continued to put the odds of a recession by the end of 2020 at 30%-35%, though he warned the probability would rise if there’s lower PMI and consumer confidence as well as higher unemployment.
• Gundlach said not to expect returns on bonds or stocks to be anywhere near where they were last year. On the U.S. Treasury market, Gundlach sees a steeper yield curve and says to be defensive on the long end of the curve.
• Negative interest rates are “fatal” for banks, according to Gundlach, who praised Fed Chair Jerome Powell for not supporting negative rates. He noted that regions that have instituted negative rates have seen their banking sectors underperform the U.S.