Bitcoin’s recent bounce has yet to dispel doubts about its vulnerability. The cryptocurrency has jumped 10% over two days and was trading at $36,993 as of 9 a.m. in London on Thursday. While the momentum may cheer bulls, a JPMorgan Chase & Co. team said backwardation in the futures market -- where the spot price is above futures prices -- is a reason for caution. “We believe that the return to backwardation in recent weeks has been a negative signal pointing to a bear market,” JPMorgan strategists led by Nikolaos Panigirtzoglou wrote in a note. They added that Bitcoin’s relatively depressed share of total crypto market value is another concerning trend.