The sell-off is a cornerstone of Prince Mohammed's Vision 2030 plan to bring in fresh revenue and diversify the economy - which is inrecession and blighted by high unemployment - away from energy exports in an era of low oil prices.
But the bankers, investors and analysts are expressing concerns including over the lack of a regulatory framework to assure would-be shareholders about how much control foreign companies could gain as a result of the stake sales, including the right to lay off staff.
Vice Minister for Economy and Planning Mohammed al-Tuwaijri told Reuters in April that, excluding Aramco, the government aimed to make $200 billion by putting large parts of the Saudi economy in private hands.
The Ministry of Economy and Planning did not immediately reply to a Reuters request for comment.
PATCHY PROGRESS
The selloff, including five percent of Aramco, is intended to improve state finances. The government posted a $79 billion deficit last year.
However, the record is patchy in the four sectors that Tuwaijri had highlighted as priorities for this year: grain silos, sports, electricity generation and water provision.
Banks recently submitted bids to advise on the privatisation of Saline Water Conversion Corporation's $7.2 billion Ras Al Khair desalination and power plant. But there has been less progress in the other three sectors.
Saudi Arabia's deputy electricity minister said in October he aimed for progress in privatising the power sector in 2018, after "some developments required us to wait".
Prospective bidders for the kingdom's state-owned grain mills have complained of an unwieldy sale process and onerous ownership rules.
Elsewhere, the Ministry of Health has put on hold its tender seeking financial advisers for the privatisation of 55 primary healthcare units in Riyadh, after receiving their bids in April, a financial source familiar with the matter said.
It then issued a new tender to seek a technical adviser on the expected costs and demand linked to the privatisation, the source said.
The Ministry of Health did not immediately reply to a Reuters request for comment.
"Compared with many of its neighbours, Saudi Arabia has only limited experience in terms of privatisations, and still lacks an adequate regulatory framework," said Raphaele Auberty, a BMI Research risk analyst for the Middle East and Africa.
Shortcomings include the absence of a framework for large-scale public-private partnership projects and a bankruptcy law, said Karen Young, a senior resident scholar at the Arab Gulf States Institute in Washington.
Saudi Post Corp's privatisation, which had at one stage been earmarked to begin early this year, has been shelved for the time being.
Abdullah Alswaha, Minister of Communications and Information Technology, told Reuters last month that Saudi Post would enter a five-year "corporatisation phase". This would turn it into a state-run company with a profit and loss responsibility before a sale to the private sector.
"It makes sense to focus more on putting that corporate DNA, leadership and resources, then think about a complete privatisation," said Alswaha.
Uncertainty has surrounded a plan to privatise soccer clubs. Earlier this year Jadwa Investment was appointed to advise on the sale of up to five soccer clubs in the Saudi Professional League, sources told Reuters in February.
The General Sports Authority did not immediately reply to a request for comment.
"At one stage it was looking like the bidding process could start as early as 2018 but recent indications perhaps suggest 2019-20 is more likely," said Steven Bainbridge, head of sports law and events management at Al Tamimi & Company, who has been fielding interest from potential clients on the process.
Confusion has been created about an airport privatisation process after some local media reported that the government intended to privatise 27 of them by the middle of 2018, a target analysts said was unrealistic.
But in an emailed reply to questions from Reuters, Faisal Hamad al-Sugair, Chairman of Saudi Civil Aviation Holding Company, said the goal was for the airports to be "corporatised", or turned into private companies, by that date. Privatisation would follow later.
"Various challenges have arisen and have been resolved. The deadline of mid-2018 is reachable," he said.