Ken Griffin's Citadel is having another good year as its flagship fund surges 9%

• Citadel is having a good year, with its flagship fund Wellington up about 9%, Bloomberg reported. 
• The gains have largely been fueled by the capital-markets firm's commodities bets. 
• The strong performance follows Citadel's record profits of $16 billion last year. 

Billionaire Ken Griffin's hedge fund Citadel is notching up another strong year.