Brent crude slipped 0.8 percent to $69.07 a barrel on Friday
A further decline in oil prices may put an end on Sunday to a Gulf stock market rally that was initiated by local investors late last week.
Brent crude slipped 0.8 percent to $69.07 a barrel on Friday after Saudi Arabia slashed its oil prices for Asian and US buyers.
Although earnings of most companies in the region have little if any correlation with oil prices, analysts say many retail investors are likely to continue taking cues from the crude market until Gulf governments present next year's budgets and show their willingness to maintain state spending.
Among companies certain to be affected by cheaper oil are petrochemical producers, which had previously enjoyed the benefits of subsidised feedstock. Lower oil prices will reduce that advantage and devalue companies' inventories.
Shares in Saudi Arabia's Yanbu National Petrochemical Co (Yansab) may come under pressure after it proposed a cash dividend of 1.5 riyals ($0.4) per share for the second half of 2014 on Thursday, down from 2.0 riyals a year earlier.
Yansab also said it would shut down its ethylene glycol plant in April next year for between 35 and 60 days of planned maintenance. The financial impact on the company from the maintenance work was estimated at around 450 million riyals ($120 million).
Oman's stock market may remain bearish after rating agency Standard & Poor's on Friday revised its outlook for the country's sovereign rating to negative from stable, citing a "view that the deterioration in the fiscal or external positions could be sharper than currently expected".
The Omani government's finances are weak compared to most of the wealthy Gulf states, so the oil price plunge is expected to put particularly heavy pressure on state spending there.
Saudi Arabia's state finances are much stronger, but S&P nevertheless cut its outlook for that country to stable from positive on Friday.