Exhibit 99.1

FOR IMMEDIATE RELEASE

Contacts:

Patrick Pedonti

Chief Financial Officer

Tel: +1-860-298-4738

Justine Stone

Investor Relations

Tel: +1- 212-367-4705

E-mail: InvestorRelations@sscinc.com

SS&C Announces Offering of Senior Notes

WINDSOR, CONNECTICUT – June 24, 2015 – SS&C Technologies Holdings, Inc. (the “Company” or “SS&C”) (NASDAQ: SSNC) today announced that it intends to commence an offering of $500 million of its senior notes due 2023 (the “Notes”).

The Company intends to use the net proceeds of the Notes offering, together with the proceeds from certain other financing transactions, to finance its pending acquisition of Advent Software, Inc. (“Advent”). Completion of the Notes offering is contingent upon consummation of the acquisition of Advent.

The Notes are being offered only to qualified institutional buyers in reliance on Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”), and outside the United States, only to non-U.S. investors pursuant to Regulation S under the Securities Act. The Notes will not be initially registered under the Securities Act or any state securities laws and may not be offered or sold in the United States absent an effective registration statement or an applicable exemption from registration requirements or a transaction not subject to the registration requirements of the Securities Act or any state securities laws.

This news release shall not constitute an offer to sell or the solicitation of an offer to buy any security and shall not constitute an offer, solicitation or sale in any jurisdiction in which such offering, solicitation or sale would be unlawful. Any offers of the Notes will be made only by means of a private offering memorandum.

Forward-Looking Statements

This release contains forward-looking statements within the meaning of the U.S. federal securities laws. All statements contained herein that are not statements of historical fact are forward-looking statements, including, without limitation, statements regarding future financial performance, funding requirements and liquidity; management’s plans and strategies for future operations, including statements relating to anticipated operating performance, cost reductions, competitive strengths or market position, acquisitions and related synergies; growth, declines and other trends in markets we sell into; the anticipated impact of adopting new accounting pronouncements; the

anticipated outcome of outstanding claims, legal proceedings, tax audits and other contingent liabilities; foreign currency exchange rates and fluctuations in those rates; general economic conditions; assumptions underlying any of the foregoing; and any other statements that address events or developments that we intend or believe will or may occur in the future. Without limiting the foregoing, the words “believes”, “anticipates”, “plans”, “expects”, “estimates”, “projects”, “forecasts”, “may” and “should” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements are accompanied by such words. Forward-looking statements are not guarantees of future performance and actual results may differ materially from those envisaged by such forward-looking statements. The factors discussed under “Item 1A. Risk Factors” included in SS&C’s Annual Report on Form 10-K for the year ended December 31, 2014, as filed with the SEC on February 26, 2015, among others, could cause actual results to differ materially from those indicated by forward-looking statements made herein and presented elsewhere by management from time to time. You should not place undue reliance on any such forward-looking statements. Forward-looking statements speak only as of the date of the report, document, press release, webcast, call or other communication in which they are made. We expressly disclaim any obligation to update our forward-looking statements, whether as a result of new information, future events or circumstances, or otherwise, except as required by law.

About SS&C Technologies

SS&C is a global provider of investment and financial software-enabled services and software focused exclusively on the global financial services industry. Founded in 1986, SS&C has its headquarters in Windsor, Connecticut and offices around the world. More than 7,000 financial services organizations, from the world’s largest institutions to local firms, manage and account for their investments using SS&C’s products and services.

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