Plunging oil prices could mean the first budget cuts for major exporter Saudi Arabia since 2002 but they are not expected to be large enough to stop growth in the Arab world's biggest economy.
The government gets about 90 percent of its revenue from oil exports and is believed to need an average oil price above $90 to balance its budget this year.
But Brent crude fell to $67 a barrel this week from $115 in June and if current prices are sustained, the budget plan for next year, expected late this month, will produce a deficit for the first time since 2009.
"There is no way for Saudi authorities to announce a bigger budget in 2015 than what they announced for 2014," said John Sfakianakis, a former adviser to the Saudi finance ministry who is now regional director of asset manager Ashmore in Riyadh.
"Unavoidably they will have to scale down the budget. (But) I do not expect the budget to be hugely lower."
As recently as last month, the International Monetary Fund predicted Saudi Arabia would enjoy a fiscal surplus of 1.6 percent of gross domestic product in 2015; now, private economists are talking of a deficit of over 1 percent.
But businessmen and economists do not expect big cuts in state spending because the government has built huge fiscal reserves to cover any deficit and its ultra-low debt levels would allow it to borrow easily if needed.
This means the economy, which grew an annual 3.8 percent in the second quarter, should continue to expand and major infrastructure projects, such as the $22.5 billion plan to build a metro rail system in Riyadh by 2019, should not be at risk.
Some analysts believe Saudi Arabia is content to see oil prices fall as a way to squeeze out competing shale oil producers in the United States, confident it has enough reserves to ride out a period of cheap oil.
Even before oil started falling in June, Saudi Arabia was curbing spending growth after several years of spectacular increases following the global financial crisis and the 2011 Arab Spring uprisings.
The current year's budget plan envisages expenditure of 855 billion riyals ($227.8 billion), a mere 4.3 percent rise from the 2013 plan and the slowest increase in a decade.
Top Saudi officials have been coy about their 2015 plans.
"The global oil situation usually in one way or another affects countries' revenues and debts, but the kingdom has always been keen on building its budgets on estimates that take all possibilities into consideration," Finance Minister Ibrahim Alassaf told a local newspaper last month.
The government usually ends up spending substantially more than its budget plan, overspending by an annual average of 25 percent in 2004-2013. So the 2015 plan could quickly change if oil prices rebound.
It seems clear, however, that the government will not be under pressure to reduce spending sharply.
Government reserves at the central bank totalled 905 billion riyals at the end of October, enough to cover an annual budget deficit of 3 percent of GDP for about 10 years. That excludes the government's other assets and its ability to borrow.
Also, Saudi Arabia funds some of its large infrastructure projects, such as housing and transportation, off-budget from a separate central bank account established to insulate them from budget fluctuations, economists said. That account contained 514 billion riyals in October.
Any drop in budget spending of, for example, 1 or 2 percent would slow economic growth but probably not dramatically, because the non-oil private sector has been booming. The sector's annual growth edged up to 4.7 percent in April-June.
Economists believe Saudi Arabia will be reluctant to cut spending on areas such as social welfare and housing because it views them as key to political stability. Similarly, its infrastructure projects aim to ensure long-term economic stability by diversifying the economy.
But the foreign aid budget could see cuts. Riyadh pledged $22.7 billion to its geopolitical allies between January 2011 and April 2014, disbursing $10.9 billion, mostly to Egypt, the IMF has said.
"We think that the financial aid will be the first to be cut if we see a further decline in oil prices," said Fahad Alturki, head of research at Jadwa Investment in Riyadh.
Reducing domestic energy price subsidies, which cost the government tens of billions of dollars every year, could also bring savings. As oil has dropped, Kuwait, Oman and Abu Dhabi have taken steps towards cutting subsidies.
However, economists say the Saudi government may still shy away from this reform.
"I do not think the current oil prices being low for only a few months will create credible pressure that will trigger any change in the subsidy policy. There needs to be a longer horizon for that to happen," Alturki said.