Exhibit 99.1

KCG ANNOUNCES CONSOLIDATED EARNINGS OF $0.24 PER DILUTED

SHARE FOR THE THIRD QUARTER OF 2015

KCG reports consolidated revenues of $377.0 million

and pre-tax earnings of $35.4 million for the quarter

JERSEY CITY, New Jersey – October 30, 2015 – KCG Holdings, Inc. (NYSE: KCG) today reported consolidated earnings of $21.9 million, or $0.24 per diluted share, for the third quarter of 2015. Included in the $35.4 million of pre-tax income are asset writedowns and other real estate related charges of $34.0 million. Excluding these items, on a non-GAAP basis, third quarter 2015 pre-tax income was $69.4 million. A reconciliation of GAAP to non-GAAP results is included in Exhibit 4.

Third Quarter Highlights

Daniel Coleman, Chief Executive Officer of KCG, said, “KCG generated strong financial results in the third quarter of 2015 amid an upturn in market conditions in the U.S. equity market. The performance was driven by KCG market making in U.S. equities as well as agency-based trading on behalf of institutional clients. The results for the quarter were lowered due to writedowns for the consolidation of current real estate as well as expenses attributable to the corporate relocation. Notwithstanding, we produced significant growth in non-GAAP pre-tax income while continuing to reduce our total shares outstanding.”

Market Making

The Market Making segment encompasses direct-to-client and non-client, exchange-based market making across multiple asset classes and is an active participant in all major cash, options and futures markets in the U.S., Europe and Asia. During the third quarter of 2015, the segment generated total revenues of $299.8 million and pre-tax income of $85.4 million. Excluding expenses related to asset writedowns of $4.4 million, the segment generated pre-tax income of $89.8 million.

During the third quarter of 2015, consolidated U.S. equity dollar volume and realized volatility for the S&P 500 rose sharply. KCG market making set a new quarterly high for exchange-listed share volume and gained approximately two percentage points in market share of retail SEC Rule 605-eligible U.S. equity share volume in spite of continued strong competition. Spreads in U.S. equities widened during August as a result of the market volatility. The results for the segment were negatively impacted by the modest deterioration in market volumes of Asian and European equities.

Mr. Coleman commented, “The market conditions in U.S. equities drove the performance of KCG direct-to-client and non-client market making. In particular, we witnessed a period of elevated, broad-based, intraday volatility in August, which served as a reminder of the significant operational leverage this firm possesses in active markets. We continue to work to diversify and attain scale in strategic asset classes.”

In the second quarter of 2015, the segment generated total revenues of $192.3 million and pre-tax income of $4.4 million. Excluding expenses related to accelerated stock-based compensation of $19.8 million, the segment generated pre-tax income of $24.2 million.

In the third quarter of 2014, the segment generated total revenues of $166.6 million and a pre-tax loss of $8.0 million. Excluding expenses related to a reduction in workforce and other employee separations of $2.8 million, the segment generated a pre-tax loss of $5.2 million.

Select Trade Statistics: U.S. Equity Market Making

Global Execution Services

The Global Execution Services segment comprises agency execution services and trading venues. During the third quarter of 2015, the segment generated total revenues of $69.7 million and a pre-tax loss of $1.1 million.

During the third quarter of 2015, institutional trading activity in U.S. equities increased market-wide. Quarter over quarter, KCG grew algorithmic execution and sales trading volume from institutional clients as well as KCG MatchIt ATS volume.

Mr. Coleman commented, “Algorithmic execution on behalf of clients as well as high-touch sales trading performed well given the heightened institutional trading activity in U.S. equities. Algorithmic execution continued to onboard new institutional clients and generate additive trade volumes and revenues. During the quarter, 13 institutional clients began using KCG algorithms and we onboarded an additional 12 new institutional investors as clients. Algorithmic execution volume from institutional clients rose 7 percent quarter over quarter and 30 percent year over year.”

In the second quarter of 2015, the segment generated total revenues of $63.5 million and a pre-tax loss of $9.9 million. Excluding expenses related to accelerated stock-based compensation of $8.2 million, the segment generated a pre-tax loss of $1.7 million.

In the third quarter of 2014, the segment generated total revenues of $79.2 million and a pre-tax loss of $1.7 million. Excluding expenses related to a reduction in workforce and other employee separations of $3.6 million, the segment generated pre-tax income of $1.9 million.

Select Trade Statistics: Agency Execution and Trading Venues

Corporate and Other

The Corporate and Other segment includes strategic investments and corporate overhead expenses. During the third quarter of 2015, the segment generated total revenues of $7.6 million and a pre-tax loss of $49.0 million. Excluding writedown of assets and other real estate related charges of $29.7 million, the segment generated a pre-tax loss of $19.3 million.

In the second quarter of 2015, the segment generated total revenues of $6.0 million and a pre-tax loss of $51.6 million. Excluding expenses related to accelerated stock-based compensation of $0.8 million, a debt make-whole premium of $16.5 million, writedown of capitalized debt costs of $8.5 million, and other real estate related charges of $6.3 million, the segment generated a pre-tax loss of $19.4 million.

In the third quarter of 2014, the segment generated total revenues of $26.5 million and a pre-tax loss of $5.5 million. Excluding a net gain related to the tradeMONSTER combination with OptionsHouse of $15.1 million and expenses related to a reduction in workforce and other employee separations of $4.2 million and a lease loss accrual of $0.3 million, the segment generated a pre-tax loss of $16.2 million.

Financial Condition

As of September 30, 2015, KCG had $628.2 million in cash and cash equivalents. Total outstanding debt was $495.4 million. The Company had $1.48 billion in stockholders’ equity, equivalent to a book value of $15.95 per share and tangible book value of $14.40 per share based on total shares outstanding of 92.5 million, including restricted stock units.

KCG’s headcount was 1,033 full-time employees at September 30, 2015 compared to 1,045 at June 30, 2015.

During the third quarter of 2015, KCG repurchased 1.2 million shares for approximately $12.2 million under the Company’s stock repurchase program.

Conference Call

KCG will hold a conference call to discuss third quarter 2015 financial results starting at 9:00 a.m. Eastern Time today, October 30, 2015. To access the call, dial 888-801-6507 (domestic) or 913-312-1424 (international) and enter passcode 202677. In addition, the call will be webcast at http://edge.media-server.com/m/p/9d4qz3ey/lan/en. Following the conclusion of the call, a replay will be available by selecting a number based on country of origin from a list posted at: https://replaynumbers.conferencinghub.com/index.aspx?confid=202677&passcode=202677 and entering passcode 202677.

Additional information for investors, including a presentation of the third quarter financial results, can be found at http://investors.kcg.com.

Non-GAAP Financial Presentations

KCG believes that certain non-GAAP financial presentations, when taken into consideration with the corresponding GAAP financial presentations, are important in understanding operating results. Selected financial information is included in the non-GAAP financial presentations for the three months ended September 30, 2015, June 30, 2015 and September 30, 2014 and for the nine months ended September 30, 2015 and September 30, 2014. KCG believes the presentations provide a meaningful summary of revenues and results of operations for each of the three and nine month periods. Reconciliations of GAAP to non-GAAP results are included in the schedules in Exhibit 4.

About KCG

KCG is a leading independent securities firm offering investors and clients a range of services designed to address trading needs across asset classes, product types and time zones. The firm combines advanced technology with exceptional client service across market making, agency execution and venues. KCG has multiple access points to trade global equities, fixed income, currencies and commodities via voice or automated execution. www.kcg.com

Certain statements contained herein may constitute “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. Forward-looking statements are typically identified by words such as “believe,” “expect,” “anticipate,” “intend,” “target,” “estimate,” “continue,” “positions,” “prospects” or “potential,” by future conditional verbs such as “will,” “would,” “should,” “could” or “may,” or by variations of such words or by similar expressions. These “forward-looking statements” are not historical facts and are based on current expectations, estimates and projections about KCG’s industry, management’s beliefs and certain assumptions made by management, many of which, by their nature, are inherently uncertain and beyond our control. Any forward-looking statement contained herein speaks only as of the date on which it is made. Accordingly, readers are cautioned that any such forward-looking statements are not guarantees of future performance and are subject to certain risks, uncertainties and assumptions that are difficult to predict including, without limitation, risks associated with: (i) the strategic business combination (the “Mergers”) of Knight Capital Group, Inc. (“Knight”) and GETCO Holding Company, LLC (“GETCO”); (ii) difficulties and delays in fully realizing cost savings and other benefits of the Mergers and the inability to manage trading strategy performance and sustain revenue and earnings growth; (iii) the sale of KCG Hotspot; (iv) changes in market structure, legislative, regulatory or financial reporting rules, including the increased focus by Congress, federal and state regulators, the SRO’s and the media on market structure issues, and in particular, the scrutiny of high frequency trading, alternative trading systems, market fragmentation, colocation, access to market data feeds, and remuneration arrangements such as payment for order flow and exchange fee structures; (v) past or future changes to KCG’s organizational structure and management; (vi) KCG’s ability to develop competitive new products and services in a timely manner and the acceptance of such products and services by KCG’s customers and potential customers; (vii) KCG’s ability to keep up with technological changes; (viii) KCG’s ability to effectively identify and manage market risk, operational and technology risk (such as the events that affected Knight on August 1, 2012), legal risk, liquidity risk, reputational risk, counterparty and credit risk, international risk, regulatory risk, and compliance risk; (ix) the cost and other effects of material contingencies, including litigation contingencies, and any adverse judicial, administrative or arbitral rulings or proceedings; (x) the effects of increased competition and KCG’s ability to maintain and expand market share; and (xi) the announced plan to relocate KCG’s global headquarters from Jersey City, NJ to New York, NY. The list above is not exhaustive. Because forward looking statements involve risks and uncertainties, the actual results and performance of KCG may materially differ from the results expressed or implied by such statements. Given these uncertainties, readers are cautioned not to place undue reliance on such forward-looking statements. Unless otherwise required by law, KCG also disclaims any obligation to update its view of any such risks or uncertainties or to announce publicly the result of any revisions to the forward-looking statements made herein. Readers should carefully review the risks and uncertainties disclosed in KCG’s reports with the U.S. Securities and Exchange Commission (“SEC”), including those detailed under “Certain Factors Affecting Results of Operations” in the MD&A and in “Risk Factors” in Part I, Item 1A of KCG’s Annual Report on Form 10-K for the year ended December 31, 2014, and in Part II, Item 1A of the Company’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2015, and in other reports or documents KCG files with, or furnishes to, the SEC from time to time. This information should be read in conjunction with KCG’s Consolidated Financial Statements and the Notes thereto contained in the Quarterly Report on Form 10-Q for the quarter-ended June 30, 2015, and in other reports or documents KCG files with, or furnishes to, the SEC from time to time.