Regulatory Requirement	9 Months Ended
Sep. 30, 2017
Regulatory Requirement
Regulatory Requirement	16. Regulatory Requirement As of September 30, 2017, three broker-dealer subsidiaries of the Company are subject to the SEC Uniform Net Capital Rule 15c3-1, which requires the maintenance of minimum net capital of $1.0 million for each of the three broker-dealer subsidiaries. At September 30, 2017, the subsidiaries had net capital of approximately $368,1 million, $48.3 million and $11.6 million, which was approximately $367.1 million, $47.3 million and $10.6 million in excess of the required net capital of $1.0 million required for each of the three subsidiaries. At December 31, 2016, prior to the KCG Acquisition, the Company’s subsidiaries had net capital of approximately $74.5 million and $10.8 million, which was approximately $73.5 million and $9.8 million in excess of the required net capital of $1.0 million and $1.0 million, respectively. Pursuant to NYSE and NYSE MKT (formerly NYSE Amex) rules, one of the broker-dealer subsidiaries was required to maintain $1.9 million of capital in connection with the operation of its DMM business as of December 31, 2016. The required amount is determined under the exchange rules as the greater of $1 million or 15% of the market value of 60 trading units for each symbol in which the broker-dealer subsidiary is registered as the DMM. The Company sold its DMM assets in September 2017.

16. Regulatory Requirement

As of September 30, 2017, three broker-dealer subsidiaries of the Company are subject to the SEC Uniform Net Capital Rule 15c3-1, which requires the maintenance of minimum net capital of $1.0 million for each of the three broker-dealer subsidiaries. At September 30, 2017, the subsidiaries had net capital of approximately $368,1 million, $48.3 million and $11.6 million, which was approximately $367.1 million, $47.3 million and $10.6 million in excess of the required net capital of $1.0 million required for each of the three subsidiaries. At December 31, 2016, prior to the KCG Acquisition, the Company’s subsidiaries had net capital of approximately $74.5 million and $10.8 million, which was approximately $73.5 million and $9.8 million in excess of the required net capital of $1.0 million and $1.0 million, respectively.

Pursuant to NYSE and NYSE MKT (formerly NYSE Amex) rules, one of the broker-dealer subsidiaries was required to maintain $1.9 million of capital in connection with the operation of its DMM business as of December 31, 2016. The required amount is determined under the exchange rules as the greater of $1 million or 15% of the market value of 60 trading units for each symbol in which the broker-dealer subsidiary is registered as the DMM. The Company sold its DMM assets in September 2017.