Citing three people with knowledge of the matter, Bloomberg said it would be the first sovereign loan in at least 15 years to the kingdom, the world's biggest oil exporter.
The five-year loan is expected to be signed by the end of this month, said Bloomberg's sources, who asked not to be identified as the information is private.
They said US, European, Japanese and Chinese banks are lending the funds at about 120 basis points above London's interbank offered rate.
Riyadh posted a record budget deficit of USD 98 billion in 2015 and projects an USD 87 billion shortfall for this year.
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The shortfall has been covered by the kingdom's significant fiscal reserves, which dropped to USD 611.9 billion at the end of 2015 from USD 732 billion a year before, Saudi Arabia's Jadwa Investment said in a February report.
Riyadh took the unprecedented step of raising retail fuel prices by up to 80 percent in December and cutting subsidies for electricity, water and other services.
It has also delayed some major projects and mooted privatisations and the imposition of taxes.
On Monday the kingdom is to announce its "vision" for future social and economic development, including a "National Transformation Programme" aimed at diversifying the economy away from oil, which still accounts for more than 70 percent of state revenues.
Agencies have lowered Saudi Arabia's long-term credit ratings. Fitch Ratings earlier this month downgraded Riyadh to AA- from AA due to the "major negative implications" of the plunge in oil prices.