* Oil producers Abu Dhabi, Kuwait have close ties to Riyadh
* Aramco valuation scaled back from $2 trillion target
* Roadshows outside Gulf scrapped after limited interest (Adds analyst comment, details of IPO)
By Rania El Gamal, Hadeel Al Sayegh and Saeed Azhar
DUBAI/ABU DHABI, Nov 27 (Reuters) - Saudi Arabia's wealthy Gulf neighbours plan to invest in the initial public offering (IPO) of Saudi Aramco, sources familiar with the matter said, helping out Riyadh as it strives to raise $25.6 billion from a domestic listing of the state oil giant.
Aramco has struggled to secure an anchor investor for the listing and found little interest beyond the Gulf, forcing Riyadh to scale back ambitions for the IPO, although it would still be the world's biggest if it raises more than $25 billion.
Aramco officials have held talks on investing with Kuwait and Abu Dhabi, both oil producing states that have close ties to Saudi Arabia and both with big sovereign funds, after Riyadh scrapped plans for roadshows outside the Gulf.
Abu Dhabi Investment Authority (ADIA) was considering investing at least $1 billion, five sources told Reuters, while one of the sources said a final decision on the amount was still required board approval.
Kuwait Investment Authority (KIA) also planned to invest in the IPO, two of the sources said, although the size of Kuwaiti commitment was not immediately clear.
ADIA and Aramco declined to comment. KIA did not immediately respond to a request for comment.
Saudi Arabia aims to sell a 1.5% stake in Aramco, valuing the company at $1.6 trillion to $1.7 trillion, a lower valuation than the $2 trillion target initially sought by Crown Prince Mohammed bin Salman, known as MbS, who has made the offering a cornerstone of his economic diversification programme.
Jason Tuvey, senior emerging markets economist at Capital Economics, said that any Gulf state investment in the IPO would be "purely a political decision rather than anything (else)."
He said commitments by Abu Dhabi and Kuwait, which both sit on huge oil reserves of their own, would be "to show their support to MbS and his plans to diversify the Saudi economy."
ADIA, estimated to have assets of nearly $700 billion, is chaired by the president of the United Arab Emirates and its deputy chairman is Abu Dhabi Crown Prince Sheikh Mohammed bin Zayed al-Nahyan, a close ally of the Saudi crown prince.
When Aramco's IPO plans were first flagged in 2016, an international listing was seen as one of the central elements, prompting interest among exchanges from New York to Singapore.
But many foreign institutional investors have said Aramco's valuation looked expensive and raised concerns about political, governance and environmental issues.
The head of the biggest refiner in Japan, a major Saudi oil importer, said Japanese firms were unlikely to invest because of difficulties in valuing the Saudi firm. Malaysian and Russian oil firms also said they would not invest.
The sale process for listing Aramco on Riyadh's Tadawul exchange kicked off on Nov. 3. Lead manager Samba Capital said retail subscriptions reached 27.04 billion Saudi riyals ($7.21 billion) on Tuesday, ahead of Thursday's deadline.
The offering to institutional investors, expected to raise about two thirds of the offering, closes on Dec 4.
Two sources said ADIA was considering investing at least $1 billion. Two others gave a range of $1.5 billion to $2 billion.
The Abu Dhabi and Kuwaiti sovereign funds manage a combined total of about $1.3 trillion in assets, according to the Sovereign Wealth Fund Institute, making them among the biggest sovereign funds in the world. (Additional Stanley Carvalho in Abu Dhabi and Davide Barbuscia in Dubai; Editing by Dale Hudson and Edmund Blair)