Saudi authorities are aiming to list up to 5 percent of the world's largest oil producer on both the Saudi stock exchange in Riyadh, the Tadawul, and one or more international markets in an IPO that could raise $100 billion (£80 billion).

HSBC Saudi Arabia, a joint venture between Saudi British Bank (>> Saudi British Bank SJSC) and HSBC (>> HSBC Holdings plc), NCB Capital (>> National Commercial Bank SJSC), Samba Capital (>> Samba Financial Group), Saudi Fransi Capital (>> Banque Saudi Fransi), Riyad Capital (>> Riyad Bank) and GIB Capital, the investment banking arm of Bahrain-based Gulf International Bank [GLFBK.UL], submitted proposals to Aramco in early February, the sources said.

Aramco is also considering proposals from international banks for the global share offering, with a source saying on Feb. 17 that JPMorgan (>> JPMorgan Chase & Co.) was close to being selected as an underwriter. Aramco also recently chose boutique investment bank Moelis & Co (>> Moelis & Co) as an adviser.

Two of the sources on Tuesday said bank appointments for the local mandate were expected before the end of the month.

Aramco did not immediately respond to a Reuters request for comment.

The local role will entail working with regulators at Saudi's Capital Market Authority to prepare for the Tadawul listing, which is expected to be smaller than the international portion, the sources said.

HSBC declined to comment while the other companies did not immediately respond to email requests for comments.

Officials hope the company could be valued at around $2 trillion, which would allow them to raise as much as $100 billion from investors.

Saudi Arabia is considering two options for the shape of Aramco when it sells shares in the national oil giant next year: a global industrial conglomerate, and a specialised international oil company, industry and banking sources have told Reuters.

(additional reporting by Celine Aswad in Dubai and Reem Shamseddine in Khobar; Editing by Louise Heavens, Greg Mahlich)

By Hadeel Al Sayegh, Tom Arnold and Katie Paul