"Onyx Investments has bought a 15 percent stake in Hapag-Lloyd," the official at Oman Investment Fund, who declined to be named and did not give a value for the deal, told Reuters.
German daily Frankfurter Allgemeine Zeitung, citing unnamed sources, reported on Monday that HNA -- China's fourth-largest airline group -- was also interested in buying a stake of up to 15 percent in the world's fourth-largest container shipping line.
A pubic listing of Hapag-Lloyd had been on the cards for many months but the group's owners delayed a decision on whether the company should float last month, after the Japanese earthquake and tsunami disaster and unrest in the Arab world rocked markets.
Klaus-Michael Kuehne, majority owner of logistics group Kuehne & Nagel -- part of the Albert Ballin investor group which owns 50.2 percent of Hapag-Lloyd -- was involved in the negotiations, Frankfurter Allgemeine Zeitung said.
The owners of Hapag-Lloyd in December picked Credit Suisse, Goldman Sachs and Greenhill to start preparations for a listing.
TUI aims to sell about half its stake in Hapag-Lloyd and is expected to buy back the shares it does not own in TUI Travel with the proceeds.