Because their trades were cleared through MF Global, their accounts were frozen, their positions left at the mercy of the market.

FORBES: Anger Builds Over MF Global Mess - And Spells Trouble

Customers of PFGBest, like those of MF Global last year, have had their accounts frozen and are wondering when, or if, they will see any of their money.

FORBES: PFGBest's Bad Week

In 2004 alone, 11% of surviving plans were frozen to new contributions, according to Barclays Global Investors.

FORBES: Magazine Article