One source said that the final decision on the size of the investment had not yet been taken and would need the approval of the Board of Directors of the Authority.
The agency, whose assets are estimated at $ 700 billion, is headed by UAE President Sheikh Khalifa bin Zayed Al Nahyan and Deputy Chairman of the Abu Dhabi Crown Prince Sheikh Mohammed bin Zayed Al Nahyan.
A spokesman for the agency declined to comment and Aramco declined to comment.
Two sources said the agency was considering investing at least $ 1 billion, while two others said the size of the investment was between $ 1.5 billion and $ 2 billion.
Saudi oil giant Aramco is struggling to attract a major or major investor to take part in the offer, which could be the world's largest. Aramco reached out to the Kuwait Investment Authority (KIA) and GIC in Singapore.
Aramco has canceled promotional tours for inclusion outside the Gulf region in the absence of interest from foreign institutional investors, many of whom see Aramco's valuation too expensive given concerns about policy, governance and environment issues.
Saudi Arabia aims to sell a 1.5 percent stake in Aramco in a deal valued at between $ 1.6 and $ 1.7 trillion, less than the initial $ 2 trillion target sought by Crown Prince Mohammed bin Salman. The prince has made the offering the cornerstone of his ambitious drive to diversify the kingdom's economy.