The market dipped into bear market territory on Christmas Eve when it dropped dropping 20 percent from its 52-week high. Stocks have since staged a strong comeback from the massive December sell-off with the gaining nearly 19 percent from Christmas Eve low and more than 11 percent year to date.

"The stock market was and still is in a bear market," the founder and chief executive officer of Doubleline Capital said in an investor webcast on Tuesday. He also said stocks could go negative again in 2019.

After a stellar rebound, Jeffrey Gundlach still thinks stocks are in a bear market.

Gundlach credited the market rebound to the "180-degree turn" from the Federal Reserve. Fed Chairman Jerome Powell recently signaled a "patient" approach to rate hikes and said the central bank is prepared to 'adjust' balance sheet unwind if needed. The Fed chief rattled investors in December when he described the balance sheet roll-off as being on "autopilot."

But the weakening economic data from the U.S. are sending bearish signals. Gundlach, in the webcast, highlighted the deteriorating hard and soft data and the collapse in December retail sales.

The so-called bond king and respected prognosticator on financial markets oversees $120 billion of assets under management.

This is a developing story. Check back for updates.