Wilmington-based Pharmaceutical Product Development LLC’s owners have made a deal to recapitalize and add two new investors, according to an announcement Wednesday.

A subsidiary of the Abu Dhabi Investment Authority (ADIA) and an affiliate of GIC, Singapore’s sovereign wealth fund, will now be direct investors. Both are longtime investors in private equity firms The Carlyle Group and Hellman & Friedman. Affiliates of Hellman & Friedman and Carlyle bought PPD in 2011 for about $3.6 billion and returned it to a privately held company.

The new deal, which values PPD at more than $9 billion, is expected to close in the second quarter of this year, according to a news release from PPD, a contract research organization founded by Fred Eshelman in 1985.

The deal is subject to regulatory approvals.

Under the agreement, Hellman & Friedman and Carlyle will maintain joint ownership of PPD, with Hellman assuming majority ownership. Both will invest equity from new funds into the company, according to the release.

“In connection with the transaction, PPD expects to raise approximately $550 million through the issuance of new senior unsecured holdco notes,” the release stated. “The proceeds from the investments of Hellman & Friedman, Carlyle, ADIA and GIC and the issuance of the new notes will be used to finance the recapitalization.”

PPD officials said its board, after looking at all the options, found that a deal led by its existing owners was the best route for the company and its stakeholders.

“PPD is stronger and healthier than it’s ever been since going private in late 2011 and has progressed its strategy to reduce the time and cost of drug development for our customers,” David Simmons, chairman and CEO of PPD, said in a statement. “We are excited to continue our partnership with Hellman & Friedman and Carlyle and look forward to working with our new investors, GIC and ADIA.”

PPD has more than 19,000 employees worldwide and about 1,500 in Wilmington.

Talks of whether PPD would seek a new buyer or go public have circulated since late 2015. The company has grown its footprint in the industry of helping pharmaceutical companies run clinical trials, with additional facilities and new lines of focus.

“PPD’s performance since 2011 has been exceptional,” Allen Thorpe, managing director of Hellman & Friedman, said in the release. “We are thrilled to announce this transaction and mark the beginning of the next chapter of PPD’s success. Increasing our investment reflects our confidence in the outstanding team of people throughout the company and PPD’s leadership position in the CRO industry. PPD is making the hard work of innovating new therapies easier for thousands of researchers and doctors, and we're proud to support its continued growth.”

Officials with Carlyle, which would “retain a substantial minority position in PPD,” also spoke to the company’s next chapter.

“PPD has strengthened its platform immensely and today is positioned as one of the most innovative CROs in the market,” Stephen H. Wise, managing director and global head of health care for Carlyle, said in the release. “This new capital structure is designed to support the strategy of the company and drive continued strong growth.”