The year was 2001 and Luis Castro was newly settled into his managerial role at KPMG's San José legal division, having been made partner two years earlier. At just 29, he was leading the prestigious accounting firm's legal operations in Costa Rica, supported by a team of 20 lawyers. Things were going well for the young Georgetown graduate. "Then Enron happened," he recalls. In December that year, the US energy company filed for bankruptcy amid mounting allegations of systemic accounting fraud. The US$23 billion meltdown of the former blue-chip company sent shockwaves throughout the business world and resulted in the collapse of Enron's accounting firm, Arthur Andersen. As the Big Five became the Big Four, KPMG kicked into damage limitation mode, implementing a raft of measures so it would never face the same fate as its rival. These changes altered Castro's career path for good. "We were under tremendous pressure to implement [compliance] controls," he says. "It became apparent very quickly that the firm's lawyers were to become second-class citizens as KPMG focused on its core activities and we decided it was time to leave."