Federal prosecutors are preparing to announce criminal charges as early as this week against SAC Capital Advisors LP, the hedge-fund giant that has been the target of a multiyear investigation into alleged insider trading, the Wall Street Journal reported today. The planned charges against SAC would mark the culmination of a years-long probe into suspected securities fraud at one of the biggest, most successful hedge-fund firms in the country. The action is anticipated barring any last-minute pact with SAC or other reversal of government strategy. SAC had roughly $15 billion in assets as of the beginning of 2013 and around 1,000 employees. While criminal charges against the firm would deal a huge blow to the firm’s founder and namesake, Steven A. Cohen, prosecutors aren’t planning charges against him personally.