Tough luck. On Thursday, Wall Street’s regulator, the Securities and Exchange Commission, won its first suit against an employee of a big American bank involved in bad mortgage deals sold to investors before the financial crash. Fabrice Tourre, a former trader at Goldman Sachs, was found liable on six of seven charges and faces a fine or a ban from Wall Street. Observers have criticized the pursuit of a midlevel employee rather than the bank’s executives. In 2010, the SEC charged Goldman with fraud, but settled for $550 million.