To be able to file a 13G instead of a 13D, the party must own between 5% and 20% in the company. It must also be clearly understood that the party acquiring the stake in the company is only a passive investor, and does not intend to exert control. If these criteria are not met, and if the size in the stake exceeds 20%, a 13D must be filed.
The following are registered by SEC as those files 13G and13D from Jan to Feb 14, 2013.
LaGrange Capital Administration, L.L.C.
Capital Research Global Investors
WELLS FARGO & COMPANY/MN
DIMENSIONAL FUND ADVISORS LP
Lee Munder Capital Group, LLC
STADIUM CAPITAL MANAGEMENT LLC
MSD CAPITAL L P
ROBOTTI ROBERT
It looks like this are the big owners of the stock, provided they still hold it!!!