NEW YORK ( TheStreet) -- The light at the end of the loan-loss tunnel grew brighter over the past week, as the Big Four U.S. banks issued earnings reports with a largely optimistic spin. A couple even earned money. But the question for investors is no longer when credit costs will peak; it's when industry earnings will return to "normal" again -- without the help of hedging and other market activity. Executives and analysts have been trying to provide their best-guess answers to that question. The time horizon and vagueness varies with their level of optimism and their experience in economic cycles. The consensus seems to be something along the lines of, "It might take two years...or three...or perhaps four. Here are a bunch of complicated models to help you predict it, but we really don't know." Given the punitive regulations likely to be imposed upon the banking industry, it may not even matter. Major equity indexes plunged on Thursday after President Obama unveiled more tough rules aimed at Wall Street, and bank stocks took it on the nose. The Dow Jones Industrial Average posted its biggest two-day losing streak in months, dropping more than 200 points, or 2%, at times on Thursday. Financial loss-leaders were down 5% to 8% in intraday trading. As the largest U.S. bank, Bank of America ( BAC) may be the best indicator of where the country's economic cycle stands. CFO Joe Price assured investors this week that "we are past the peak in total credit costs." And newly installed CEO Brian Moynihan asserted "we still have several quarters before we can discuss the actual, normalized earnings."