Key TakeawaysCharles Schwab shares fell after reporting its earnings and revenue declined in the fourth quarter as interest revenue dropped and it paid a regulatory charge.Profit was cut nearly in half, and interest revenue slumped 30% from a year ago.A Federal Deposit Insurance Corporation charge of $172 million made up about one-third of the company's increased expenses in the period.Charles Schwab (SCHW) shares sank close to 3% in early trading Wednesday after the discount brokerage and financial service ...