Goldman Sachs has suspended work on a planned U.S. IPO for Chinese conglomerate HNA Group's IT outsourcing unit Pactera, four people familiar with the matter told Reuters.

One of the sources, who could not be identified as the negotiations are not public, said the Wall Street bank shelved the project after the deal failed to meet the bank's internal due diligence requirements, or know-your-customer checks.

Reuters reported in July that HNA had tapped Goldman to work on the U.S. initial public offering of Pactera, a Beijing-based firm it bought from Blackstone last year for $675 million in cash. The unit was renamed HNA Ecotech Panorama Cayman Co earlier this year.

Goldman declined to comment. Representatives at HNA and Pactera did not immediately respond to requests for comment.

The sources said Goldman's departure, even temporarily, could delay Pactera's overall plan, which had been for a listing next year.

Pactera had initially sought to close a $200 million pre-IPO round in the third quarter of 2017, and to list the business early 2018.

Goldman was not officially mandated for the IPO, which had been in the early stages, but had been tapping investors for the firm's pre-IPO fundraising round.

The sources said Pactera was pressing ahead even without Goldman, as it hopes to act as a listed vehicle for HNA's Ecotech arm, focused on technology investments. It is currently seeking to raise capital through convertible bonds, two of the sources said.

HNA, one of China's most acquisitive conglomerates, has seen its banking relationships put to test since the summer, as Beijing cracks down on excessively splashy deals.

China's banking regulator in June ordered a group of lenders to assess their exposure to offshore investments by a handful of acquisitive groups, including HNA.

The New York Times reported in July that Bank of America Merrill Lynch had pulled back from working with the group due to its opaque ownership stricture. HNA Chief Executive Adam Tan said later that BAML had not dealt closely with the group. The sources said Goldman had not severed ties with HNA, adding due diligence checks are made separately for every deal.