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Institutional Investment Manager
GROUP ONE TRADING LLC
GROUP ONE TRADING LLC (CIK: 0000932540) incorporated in Delaware, located at 425 S Financial Place, Chicago, IL. Institutional holdings reported to the SEC.

Institutional Holdings (2015Q1)
Portfolio Summary: 4,755 holdings with a total value of $6,369,518,000.
#
Name
Shares
Value ($)
%
Options
Notes
1 SALIX PHARMACEUTICALS INC 1,415,400 244,595,000 3.84% Call
2 SALIX PHARMACEUTICALS INC 1,183,500 204,521,000 3.21% Put
3 ACTAVIS PLC 492,300 146,518,000 2.30% Put
4 SALIX PHARMACEUTICALS INC 516,177 89,201,000 1.40%
5 ACTAVIS PLC 203,900 60,685,000 0.95% Call
6 TIME WARNER CABLE INC 351,700 52,713,000 0.83% Put
7 HERBALIFE LTD 1,198,500 51,248,000 0.80% Call
8 AMERICAN AIRLS GROUP INC 921,000 48,610,000 0.76% Put
9 VALEANT PHARMACEUTICALS INTL PUT 235,300 46,735,000 0.73% Put
10 PHARMACYCLICS INC 179,400 45,917,000 0.72% Call
11 ABBVIE INC 764,800 44,771,000 0.70% Put
12 LUMBER LIQUIDATORS HLDGS INC 1,414,900 43,551,000 0.68% Put
13 AMERICAN AIRLS GROUP INC 794,218 41,919,000 0.66%
14 MALLINCKRODT PUB LTD CO 304,200 38,527,000 0.60% Put
15 ALLERGAN PLC 123,829 36,854,000 0.58%
16 HERBALIFE LTD 842,600 36,030,000 0.57% Put
17 BARCLAYS BK PLC 1,389,600 35,615,000 0.56% Put
18 VALEANT PHARMACEUTICALS INTL 176,200 34,997,000 0.55% Call
19 KINDER MORGAN INC DEL 826,200 34,750,000 0.55% Call
20 SEARS HLDGS CORP PUT 819,300 33,903,000 0.53% Put
21 MANNKIND CORP 5,990,900 31,153,000 0.49% Call
22 BLACKBERRY LTD 3,333,000 29,764,000 0.47% Put
23 LUMBER LIQUIDATORS HLDGS INC 917,700 28,247,000 0.44% Call
24 TIME WARNER CABLE INC 185,400 27,788,000 0.44% Call
25 KRAFT FOODS GROUP INC 317,400 27,650,000 0.43% Call
26 FIDELITY NATIONAL FINANCIAL 732,900 26,941,000 0.42% Put
27 GILEAD SCIENCES INC 260,100 25,524,000 0.40% Put
28 TARGA RES CORP 261,100 25,011,000 0.39% Call
29 BIOMARIN PHARMACEUTICAL INC 199,300 24,837,000 0.39% Put
30 RITE AID CORP 2,800,600 24,337,000 0.38% Call
31 ABBVIE INC 393,155 23,015,000 0.36%
32 TARGA RES CORP 235,900 22,597,000 0.35% Put
33 INTEROIL CORP 476,900 22,004,000 0.35% Put
34 ABBVIE INC 372,900 21,830,000 0.34% Call
35 RAPTOR PHARMACEUTICAL CORP 2,002,800 21,770,000 0.34% Put
36 CELLDEX THERAPEUTICS INC NEW 778,400 21,694,000 0.34% Put
37 BLACKBERRY LTD 2,392,403 21,364,000 0.34%
38 Mobileye NV 487,900 20,506,000 0.32% Put
39 TAIWAN SEMICONDUCTOR MFG LTD 872,200 20,479,000 0.32% Put
40 YPF SOCIEDAD ANONIMA 742,700 20,387,000 0.32% Put
41 AMERICAN AIRLS GROUP INC 371,300 19,597,000 0.31% Call
42 KRAFT FOODS GROUP INC 219,200 19,096,000 0.30% Put
43 SOLARCITY CORP 369,200 18,933,000 0.30% Call
44 HERTZ GLOBAL HOLDINGS INC 862,500 18,699,000 0.29% Put
45 PHARMACYCLICS INC 72,800 18,633,000 0.29% Put
46 BAKER HUGHES INC 288,800 18,362,000 0.29% Put
47 BIOMARIN PHARMACEUTICAL INC CALL 143,900 17,933,000 0.28% Call
48 SEADRILL LIMITED 1,917,100 17,925,000 0.28% Put
49 AMERICAN RLTY CAP PPTYS INC 1,819,500 17,922,000 0.28% Call
50 STAPLES INC 1,082,500 17,629,000 0.28% Call
Page 1 of 96

Portfolio data is normalized using SEC Form 13F filings, including the Original 13F-HR (0000932540-15-000007, filed 2015.05.14).

From 2023-01-03 onward, the SEC requires values to be reported in nearest dollars. Earlier filings reported values in thousands; therefore, positions shown as $0 in older filings may represent actual values between $0–$999.