Chinese mainland conglomerate HNA Group said that it is seeking buyers for its majority stake in Spain's NH Hotel Group amid liquidity concerns.

The conglomerate, which also owns China's fourth-largest airline Hainan Airlines, is the biggest shareholder in NH. It has hired JP Morgan and Benedetto, Gartland & Co to scout for potential buyers.

HNA holds a 29.5 percent share of NH, which is valued at about 630 million euros ($770 million), based on the closing price of NH last Friday.

Currently, NH Hotel operates about 400 hotels in more than 30 countries. It earlier said that by 2020, it plans to open 120 to 150 hotels in China. In 2013, when HNA invested in the hotel, it was suffering losses. After debt reconstruction, the company turned the loss into profit in 2015.

"The government has adjusted its policies over the supervision of overseas investments, and the lending rates at banks have been higher," said Lin Zhijie, an aviation industry analyst and columnist at Carnoc, one of China's largest civil aviation web portals.

"In the past few years, HNA has been a bit aggressive in its overseas mergers and acquisitions, and it is facing financial difficulties due to stricter controls. In the long term, it needs to strengthen the confidence of the market and investors. It is also a considerable option to adjust its business structure and sell some non-core assets to maintain financial liquidity," he said.

Since 2010, HNA has acquired around 40 overseas assets to recombine and step up its global expansion, and the total transaction amount has exceed $40 billion. Its assets span airlines, logistics providers, catering groups, hotels, financial institutions and office buildings, according to data from Morning Whistle Group, an online platform that offers information on overseas mergers and acquisitions.

Currently, there are eight A-share listed companies and three Hong Kong-listed companies under HNA. Recently, five listed companies under the group suspended trading pending major announcements. Those companies include Caissa Tourism Group, Bohai Leasing, Tianhai Investment, and CCOOP group, an e-business platform owned by HNA.

Chen Feng, co-founder and chairman of HNA Group, had earlier admitted that the company was facing liquidity problems. Chen, however, was optimistic that the company could tide over the problem and would continue to get support from banks and other financial institutions.

On Monday, HNA Innovation Co, Zhejiang Haiyue Co Ltd, and HNA Infrastructure Investment Group, which are all under HNA, saw their shares fall by the daily limit of 10 percent.

Other sub-affiliates under HNA also did not fare well on Monday. Yeland Group Co Ltd saw its shares fall by 3.38 percent to 3.43 yuan (54 cents). Northeast Electric Development Co Ltd declined 3.85 percent to 4 yuan.