EXHIBIT 21.1

SUBSIDIARIES OF PENSON WORLDWIDE, INC.

1.	SAI Holdings, Inc. (a Texas corporation)
2.	Penson Financial Services, Inc. (a North Carolina corporation that is a subsidiary of SAI Holdings, Inc.)
3.	Nexa Technologies, Inc. (a Delaware corporation that is a subsidiary of SAI Holdings, Inc.)
4.	Penson Holdings, Inc. (a Delaware corporation that is a subsidiary of SAI Holdings, Inc.)
5.	Penson Execution Services, Inc. (a Delaware corporation that is a subsidiary of SAI Holdings, Inc.)
6.	Penson Financial Futures, Inc. (a Delaware corporation that is a subsidiary of SAI Holdings, Inc.)
7.	Penson Financial Services Limited (a company incorporated in England that is a subsidiary of Penson Holdings, Inc.)
8.	Worldwide Nominees Ltd. (a company incorporated in England that is a subsidiary of Penson Financial Services Limited)
9.	Penson Financial Services Canada Inc. (a Canadian corporation that is a subsidiary of Penson Holdings, Inc.)
10.	Penson Ventures, Inc. (a Canadian corporation that is a subsidiary of Penson Holdings, Inc.)
11.	Penson Asia Limited (a Hong Kong company that is a subsidiary of Penson Holdings, Inc.)
12.	Market Essentials Group, Inc. (a Canadian corporation that is a subsidiary of Penson Ventures, Inc.)
13.	Turnpike Trading Systems, Inc. (a Canadian corporation that is a subsidiary of Penson Ventures, Inc.)
14.	GHP1, Inc. (a Texas corporation that is a subsidiary of SAI Holdings, Inc.)
15.	GHP2, LLC (a Delaware limited liability company that is a subsidiary of GHP1, Inc.)
16.	Penson Futures (an Illinois general partnership that is a subsidiary of GHP1, Inc. and GHP2, LLC)
17.	Penson Financial Services Australia Pty Ltd (an Australian corporation that is a subsidiary of Penson Holdings, Inc.)
18.	Penson Australia Nominees Pty Ltd (an Australian corporation that is a subsidiary of Penson Financial Services Australia Pty Ltd)