Several sources said Bank of America-Merrill Lynch was advising ADNOC on a range of options for the infrastructure assets, including a possible stock market listing.
JPMorgan is also helping with the process, two of the sources said.
Bank of America-Merrill Lynch and JPM declined to comment.
Abu Dhabi is encouraging its state companies to go public, hoping to lure foreign investors with privatisations and make the economy more competitive and less reliant on oil revenues.
But the appetite for stock market listings has been hurt by the global sell-off in equities as political and economic tensions have increased and as interest rates rise in developed countries.
Abu Dhabi sovereign wealth fund Mubadala this week postponed the listing of Spanish oil business Cepsa, which would have been the largest oil company listing in a decade, citing adverse market conditions.
This follows the postponement of Saudi Aramco's share float, expected to be worth up to $100 billion, after two years of preparations.
Although ADNOC has no plans to list the holding company, it might look at selling stakes in some of its service companies and would explore new ways to manage its assets, the company's CEO told Reuters last year.
It did list 10 percent of its distribution arm, the largest operator of retail fuel service stations and convenience stores in the United Arab Emirates, in December 2017.
Its share price is trading 18 percent below the IPO price.
Sources previously told Reuters that the company was preparing to sell a further 10 percent of the shares to help with its aim of joining the MSCI Emerging Markets Index and attract more international interest.
ADNOC has also sold a 5 percent stake in the drilling business to Baker Hughes, the world's second-largest oil services company, for $550 million. urn:newsml:reuters.com:*:nL8N1WO161
The company has been increasing partnerships with international oil and gas companies, including Italy's ENI ENI.MI and France's Total TOTF.PA to expand its refining and petrochemicals operations.
ADNOC produces some 3 million barrels of oil per day, or around 3 percent of global production. It also produces more than 9.8 billion cubic feet of raw gas per day, placing it among the largest energy producers in the world.
(Reporting by Clara Denina and Dasha Afanasieva in London and Tom Arnold in Dubai; additional reporting by Rania El Gamal. Editing by Elaine Hardcastle) ((email@example.com)(+44 207 542 9420)(Reuters Messaging: firstname.lastname@example.org)(Twitter: @claradenina))