Earnings have been anything but a prerequisite for U.S. technology stocks to surge in the past 10 months. The performance of a Goldman Sachs Group Inc. index of unprofitable companies shows as much. The gauge increased almost fivefold from a record low on March 18 through last Wednesday, when it set a record. Goldman’s indicator also climbed five times as much as the S&P 500 Technology Index during the period. “These are extraordinary moves that are likely unsustainable at this point,” Jonathan Krinsky, Bay Crest Partners LLC’s chief market technician, wrote in a report Sunday that highlighted the index.