Prudential Financial ( PRU) shares were trading sharply down this afternoon after the insurer held its earnings call to explain the $166 million loss for the third quarter. Prudential's shares had opened at $35.25 in early trading on Thursday, and rose 7% in early trading. Shares then went as low as $26.11 before closing at $28.87, losing 18% for the day. It is not clear what drove the sudden drop, but clearly the market was unsettled by the lack of advice about future earnings, together with a reluctance of management to provide details about any excess capital reserves. Perhaps the market would have reacted stronger if it had heard the matter-of-fact way that CFO Richard Carbone announced to the listening analysts that Prudential was changing its accounting practices, with immediate effect, to follow SEC guidelines more closely and that $500 million in fixed-income securities that would previously have been reported as an impairment other than temporary will be recorded instead as an unrealized loss, as it considers the securities "good cash." In other words. "We are changing the way we account for assets partway through the year, because we don't want this loss to show up." Factoring in this "loss," the comparable figures would indicate a quarterly loss of $666 million; a significantly different story from the one told by the profit-and-loss statement. Naturally, the quarterly report included a significant loss on investments of $1.1 billion, and the consolidated loss of $166 million was down $1 billion from the same quarter in the prior year and a massive $2.3 billion year to date.