Saudi Arabia's green light to join the World Trade Organisation (WTO) is likely to boost shares at the start of the week but trading will slow ahead of the Eid holiday, traders said on Saturday.
The index of the Arab world's biggest stock market closed the week up fractionally at 14,998 points on Thursday, or 83 percent up from the start of the year on a booming economy and strong liquidity fuelled by high oil prices.
It could threaten the record intra-day high of 15,137 points after a WTO working party approved the final package of Saudi entry terms on Friday and agreed to pass them on for endorsement to a meeting of the body's ruling General Council next month.
Economists say smaller Saudi businesses may suffer in the short term from greater international competition when the kingdom joins the WTO, but its vibrant petrochemical sector led by SABIC is expected to prosper.
The market will close for a week on November 1 for the Eid-ul-Fitr holiday and traders say business is likely to wind down over the next few days.
"The market will gradually switch gears into quiet and slow trading, causing decline in trading volumes," Bakheet Financial Advisors said in a market report.
Bakheet said speculative buying of stocks in smaller companies picked up last week despite poor results from many of those firms, a move which it said puts investors at risk because few of the gains have been justified by fundamentals.
The main blue chip gainers last week were Saudi Fertiliser Co (SAFCO), which rose 8.0 percent and Samba Financial Group, which was up 4.8 percent.
Banque Saudi Fransi and Saudi British Bank were the biggest losers, slipping 3.7 percent and 3.1 percent respectively.