"The optimal strategy is to reduce risk on strength," Gundlach said on CNBC's " Closing Bell " Monday.
The markets just go from a mineshaft type of decline and that's true in the credit markets and I think it's true in other risk assets as well."
The S & P 500 is now on a three-day winning streak, but Treasury yields rebounded dramatically Monday, putting pressure on technology names.
He believes if the S & P 500 rises to the range between 4,200 and 4,300, it would be a good place for investors to sell.
Gundlach also stood by his call for recession, saying a downturn will be upon us in a few months.