Shares of fintech company Block (SQ -1.75%) soared 22% in December according to data provided by S&P Global Market Intelligence. There wasn't specific news sparking the jump in price, but many stocks benefited from an overall market rally in reaction to the Federal Reserve's announcement that it would cut interest rates this year. How this benefits Block Block, formerly Square, is a fintech company that operates what it calls two "ecosystems." Its original seller's business, which it still calls Square, mar ...