DANBURY, Conn., and RESEARCH TRIANGLE PARK, N.C. — Health care and pharmaceutical information specialists IMS Health Holdings Inc. and Quintiles Transnational Holdings Inc. plan to merge.

The companies said Tuesday that the deal is an all-stock merger of equals transaction, with the combined company to be named Quintiles IMS Holdings Inc. Plans call for the merged company to maintain dual headquarters in Danbury, Conn., where IMS is now based, and in Research Triangle Park, N.C., the base of Quintiles.

Ari Bousbib, chairman and chief executive officer of IMS Health, is slated to become chairman and CEO of the combined organization, with Quintiles CEO Tom Pike becoming vice chairman. The company’s board will be comprised of six directors appointed by the Quintiles board and six directors appointed by the IMS board.

Under the merger agreement, IMS Health shareholders will get 0.384 shares of Quintiles common stock for each share of IMS Health common stock. When the deal closes, IMS shareholders will own about 51.4% of the diluted shares of the combined company, and Quintiles shareholders will own about 48.6%.

Taken together, the companies have an equity market capitalization of over $17.6 billion and an enterprise value of more than $23 billion, with combined 2015 pro forma revenue of $7.2 billion.

“Together, our solutions will enable differentiation in the CRO market, advance real-world evidence [RWE] capabilities and deliver comprehensive commercial solutions for our clients,” stated Bousbib. “This powerful combination brings together leading technology and analytics with deep scientific expertise delivered on a global scale by our 50,000 immensely talented professionals in more than 100 markets. Our combined business will accelerate growth, yield greater operating efficiencies and provide more flexibility for future expansion.”

According to IMS and Quintiles, the merger will improve clinical trial design, recruitment and execution in the $100 billion biopharma product development market by melding IMS’ rich, global information solutions with Quintiles’ industry-leading product development skills. In addition, they said, Quintiles IMS will create a distinctive global RWE solutions platform by combining a leading portfolio of anonymous patient records, technology-enabled data collection and observational research experts to address critical health care issues of cost, value and patient outcomes.

“This combination addresses life science companies’ most pressing needs: to transform the clinical development of innovative medicines, demonstrate the value of these medicines in the real world and drive commercial success,” Pike commented. “We are bringing together two best-in-class leaders. I’m confident that together we will make our clients even more successful.”

IMS and Quintiles said they expect the transaction to close in the second half of this year, pending regulatory approvals, customary closing conditions, and approval by IMS Health and Quintiles shareholders.