As the financial crisis was about to explode, Merrill Lynch kept secret from analysts and investors that it had $30.4 billion in mortgage-related securities on its books — an amount that “startled” the firm’s CEO Stanley O’Neal, according to documents and interviews released by a fact-finding panel. The Financial Crisis Inquiry Commission on Thursday released a widely anticipated report on the causes of the 2008 economic meltdown. The panel focused a section of its report on interviews with Merrill Lynch executives and power-point presentations they produced demonstrating that top officials knew the company was heavily exposed to collateralized debt obligations, a type of security often composed of the riskier portions of mortgage-backed securities, but did not disclose that information to investors.