In 2006 and 2007, Goldman Sachs Group peddled more than $40 billion in securities backed by at least 200,000 risky home mortgages, but never told the buyers it was secretly betting that a sharp drop in U.S. housing prices would send the value of those securities plummeting. Goldman's sales and its clandestine wagers, completed at the brink of the housing market meltdown, enabled one of the nation's premier investment banks to pass most of its potential losses to others before a flood of mortgage loan defaults staggered the U.S. and global economies. Only later did investors discover that what Goldman promoted as triple-A investments were closer to junk. Now, pension funds, insurance companies, labor unions and foreign financial institutions that bought those dicey mortgage securities are facing large losses, and a five-month McClatchy Newspapers investigation has found that Goldman's failure to disclose that it made secret, exotic bets on an imminent housing crash may have violated securities laws. The Securities and Exchange Commission should be very interested in any financial company that secretly decides a financial product is a loser and then goes out and actively markets that product or very similar products to unsuspecting customers without disclosing its true opinion," said Laurence Kotlikoff, a Boston University economics professor who's proposed a massive overhaul of the nation's big banks. "This is fraud and should be prosecuted."