Bruce Berkowitz declined to comment about Bank of America's stock slide. Some mutual funds may have charters that restrict holding stocks below $5, but the extent of such charters may not be significant enough to be a huge market factor. When Bank of America's shares were struggling in August, Warren Buffett's Berkshire Hathaway Inc purchased $5 billion of the bank's preferred shares, providing a much needed boost in confidence in the company. When the investment became public on August 25, the shares jumped more than 9 percent to $7.65. Since then, the stock has mostly sagged. Buffett's investment also included the right to buy 700 million shares of Bank of America's common stock at $7.14 per share, but those warrants are currently under water. Bank of America chief executive officer Brian Moynihan was part of a panel discussion on the economy on Monday in Charlotte, North Carolina, but did not address his bank's stock price.