1237 GMT - Cryptocurrencies are rallying on a flurry of positive catalysts, but it remains premature to call the start of a new bull run for the asset class, Jefferies's Andrew Moss writes. The rally in crypto tokens is driven by positive signals from U.S. regulators, and the Treasury's surprise move to increase its buybacks of longer-dated U.S. government bonds. However, the sharp increase in currencies is partly driven by short covering, with investors yet to show significant enthusiasm by buying into crypto. Bitcoin jumps 5.16% to $76,774.10, pairing some of the session's earlier gains. Ethereum gains 2.3% to $2,378.54.