People familiar with the matter told Reuters news agency that Aramco's vast profits - almost three times those of Apple past year - meant investors were willing to buy the bonds even if they end up getting a lower return than on Saudi sovereign debt.
The purchase effectively merges the kingdom's two largest companies, handing PIF around the same amount it had expected from the much-delayed Aramco IPO.
The state-owned oil giant is marketing a U.S. dollar-denominated debt issue split into six tranches with maturities ranging from three to 30 years.
State-owned Aramco was expected to raise around $10bn from the deal, which will be priced later on Tuesday and is seen as a gauge of potential investor interest in the company's eventual initial public offering.
The bond sale, being pitched to investors over the last week in a global roadshow from Tokyo to NY and London, has forced Aramco to reveal financial and operational secrets held closely since the company's nationalization in the late 1970s, shedding a light on the relationship between the kingdom and its most important asset. That would be the highest order book value since a record issuance by Qatar a year ago, which attracted around $52 billion in orders. Orders tracked upwards to $85 billion by Tuesday, with pricing expected later Tuesday. And later in the bond market itself, where the Saudi government successfully raised debt this year.
The acquisition will be financed through a mixture of bonds as well as the oil company's vast cash reserves, The National reported last week.
The IPO was announced with a great deal of fanfare by the Saudi Crown Prince, Mohammed Bin Salman (MBS), and the success of the bond sale may mean that he can forego the IPO plan without losing face.
Community holds vigil for principal who died after donating bone marrow
The doctors subsequently planned to do the transplant through intravenous therapy, Nelson told the student newspaper . Still he pressed on and the doctors came up with a different method they could use to extract the bone marrow.
It would also encourage Aramco to go back to the bond markets at a later date.
Analysts said the worldwide bond had been created to help raise funds for a down payment on Aramco's $69.1bn purchase of a majority stake in Saudi petrochemicals firm SABIC, which was announced last month.
Ahead of the bond issue, Aramco revealed its accounts to global ratings agencies for the first time ever.
JPMorgan Chase & Co. and Morgan Stanley are managing the bond sale along with Citigroup Inc., Goldman Sachs Group Inc., HSBC Holdings Plc, and NCB Capital Co.
Aramco is raising money as bond investors search for higher yields.
The company plans to use some of the proceeds of the bond sale to pay for the $69 billion acquisition of a majority stake in local petrochemical company Sabic from the country's sovereign wealth fund.