Payments firm First Data to acquire CardConnect for $750 mln -companies

* First Data's largest buy since 2003 -CEO

* $750 mln deal includes all stock, debts -statement

* Target close in Q3 2017

NEW YORK, May 30 (Reuters) - First Data Corp has agreed to acquire smaller payments processing peer CardConnect Corp in a deal worth around $750 million, the companies said on Tuesday.

First Data will pay $15.00 per share in cash for CardConnect, whose stock jumped to as much as $15.15, indicating some investors expect a better offer.

The deal would be the largest acquisition by First Data since 2003 and will help bolster it as an independent software vendor and in enterprise resource planning systems, according to Chairman and CEO Frank Bisignano.

"We didn't have access to their technology and they didn't distribute all our options. We talked about expense synergies but it's the ability to grow our ISV and ERP solutions that was key," Bisignano told Reuters in a telephone interview.

ERP systems allow companies to combine different process management systems on one platform.

First Data was acquired by buyout firm KKR & Co for $29 billion in 2007, just before the global financial crisis. A $3.5 billion equity raising to help strengthen its balance sheet was completed in 2014, before an initial public offering in 2015, which raised $2.6 billion.

Reducing the company's debt has been one of Bisignano's main tasks since he was appointed CEO in 2013. Debt has fallen from around 10-times EBITDA (earnings before interest, tax, depreciation and amortization) when he arrived to low-6-times currently. It aims to be at 4-times by the end of 2019, he said.

"There are two key missions: continuing to grow the company and to pay down our debt," Bisignano said. "There are opportunities out there, and this was an incredibly attractive opportunity, so we deployed our capital accordingly."

First Data will fund the purchase with its own cash, supplemented by money from existing credit facilities, according to the statement. The deal is to close in the third quarter.

Allen & Company and FT Partners were the respective financial advisers to First Data and CardConnect. (Reporting by David French in New York; Editing by Dan Grebler)