8-K

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 8-K

Current Report

Pursuant to Section 13 or 15(d) of the Securities
Exchange Act of 1934

June 8, 2005

Date of Report (Date of earliest event reported)

INVESTMENT TECHNOLOGY GROUP, INC.

(Exact name of registrant as specified in its charter)

Delaware	0-23644	95-2848406
(State or other jurisdiction of incorporation or organization)	(Commission file number)	(I.R.S. Employer Identification No.)

380 Madison Avenue
New York, New York 10017
(Address of principal executive offices)

(212) 588-4000
(Registrant’s telephone number, including area code)

Not Applicable
(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o Written communication pursuant to Rule 425 under the Securities Act (17. CFR 230.425)

o Soliciting material pursuant to Rule 14a-2 under the Exchange Act (17. CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17. CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17. CFR 240.13e-4(c))

Item 8.01—Other Events

On June 8, 2005 Investment Technology Group, Inc. issued a press release announcing trading statistics for the month ended May 31, 2005. A copy of this press release is attached hereto as Exhibit 99.1.

Item 9.01 Financial Statements and Exhibits

(c) Exhibits
99.1	Press release issued by Investment Technology Group, Inc. on June 8, 2005.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

		INVESTMENT TECHNOLOGY GROUP, INC.
	(Registrant)
Date:  June 8, 2005			By:	/s/ Howard C. Naphtali
				Howard C. Naphtali
				Chief Financial Officer and
				Duly Authorized Signatory of Registrant

EXHIBIT INDEX

Exhibit No.	Description
99.1	Press Release by Investment Technology Group, Inc., dated as of June 8, 2005

EX-99.1

Exhibit 99.1

For Immediate Release

ITG RELEASES MAY 2005 U.S. TRADING

STATISTICS

NEW YORK, NY, June 8, 2005 — Investment Technology Group, Inc. (“ITG”) (NYSE: ITG), a leading provider of technology-based equity trading services and transaction research, today announced that U.S. trading volume was 1.9 billion shares for the month ended May 31, 2005, averaging 91 million shares per trading day. This compares to 2.1 billion shares (98 million per trading day) in April 2005 and 1.7 billion shares (84 million per trading day) in May 2004.

There were 21 trading days in both May and April 2005, and there were 20 trading days in May 2004.

Monthly volume statistics are preliminary, and accordingly may be revised in subsequent updates and public filings. Volume statistics are posted on ITG’s Web site, http://www.itginc.com, and are also available via a downloadable spreadsheet file.

ITG U.S. Trading Activity

Total U.S. Shares	# of Trade Days	Total U.S. Volume	Average U.S. Daily Volume
May:	21	1,902,247,144	90,583,197
Year-to-Date:	103	9,793,036,446	95,078,024

4

ABOUT ITG

ITG is headquartered in New York with offices in Boston, Los Angeles, Dublin, Hong Kong, London, Melbourne, Sydney, Tel Aviv and Toronto. As a leading provider of technology-based equity trading services and transaction research to institutional investors and brokers, ITG helps clients to access liquidity, execute trades more efficiently and make better trading decisions. ITG generates superior trading results for its clients through three lines of business. POSITÒ, the world’s largest equity matching system, allows clients to trade confidentially. The Electronic Trading Desk is recognized as one of the leading program trading operations in the U.S. ITG’s leading-edge Client-Site Trading Products allow users to implement their own trading strategies by providing direct electronic access to most sources of market liquidity. For additional information, visit http://www.itginc.com.

In addition to historical information, this press release may contain “forward-looking” statements, as defined in the Private Securities Litigation Reform Act of 1995, that reflect management’s expectations for the future. A variety of important factors could cause results to differ materially from such statements. These factors include the company’s ability to achieve expected future levels of sales; the actions of both current and potential new competitors; rapid changes in technology; financial market volatility; general economic conditions in the United States and elsewhere; evolving industry regulation; cash flows into or redemption from equity funds; effects of inflation; customer trading patterns; and new products and services. These and other risks are described in greater detail in the company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2004, and other documents filed with the Securities and Exchange Commission and available on the company’s web site.

Contacts:

Howard C. Naphtali	Maureen Murphy
Chief Financial	OfficerInvestor Relations
(212) 444-6160	(212) 444-6323

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