Here were the MM players that month:

GOSY >> MM MONTHLY >> JAN 2013

Total Share Volume 28,912,040

ETRF
G1 Execution Services, LLC. 9,159,268
SUNR
Sunrise Securities Corp. 8,825,000

NITE
Knight Capital Americas LLC 5,772,772
ATDF
AUTOMATED TRADING DESK FINANC 4,775,000

CSTI
CANACCORD GENUITY INC. 350,000

CDEL
Citadel Securities LLC 20,000
CANT
Cantor, Fitzgerald & Co. 10,000