BlackRock (BLK) will put forward a secondary offering of 42 million shares of its common stock. 34.5 million shares are being offered by Bank of America (BAC) and up to 7.5 million shares are being offered by PNC Financial Services Group. Bank of America will likely grant the underwriters a 30-day option to purchase an additional 6.3 million shares of BlackRock's common stock to cover over-allotments, if any. "BlackRock will not receive any of the proceeds from the sale of shares of its common stock," the investment firm said in a statement. "The sale of shares of common stock to be sold includes shares of common stock issuable upon conversion of BlackRock's Series B Preferred Stock." BofA Merrill Lynch and Morgan Stanley are serving as joint book-running managers for the offering. Write to Jacob Gaffney. The author holds no relevant investments.