Turning Up the Heat on Wall Street

Was the watchdog watching carefully enough? That was just one of the questions on Wall Street last week as fresh controversy swirled around the Street's takeover titans -- and the agency that oversees them. Widening its probe of illegal insider trading, the Securities and Exchange Commission revealed unsettling new details of the Ivan Boesky case, while disputes flared over the use of so-called greenmail tactics in takeover battles.

Most stunning was the news that the SEC had subpoenaed 15 employees of Shearson Lehman Brothers, including its chairman Peter Cohen. The agency is investigating the $482 million buyout of Sheller-Globe, a Toledo...