Bank of America Corp , the second-largest U.S. bank, on Monday said quarterly profit fell 77 percent, hurt by more than $5 billion of write-downs and credit-related costs as more borrowers fell behind on payments. First-quarter net income fell to $1.21 billion, or 23 cents per share, from $5.26 billion, or $1.16, a year earlier. Excluding merger costs, profit was 26 cents per share, below the average analyst forecast of 45 cents, according to Reuters Estimates. Results included a $776 million gain from credit card network Visa Inc's initial public offering last month. Net revenue dropped 6 percent to $17...