Saudi Arabia's stock market fell sharply on Monday, bogged down by petrochemical shares, while all major Gulf markets slipped, mostly weighed down by financial stocks.

Saudi Arabia's index fell 1.3 percent, in part due to a 7.3 percent plunge in petrochemical firm Saudi Kayan in heavy volume, despite posting a narrowed fourth-quarter net loss after zakat and tax of 110.9 million riyals ($29.57 million) from 220.3 million riyals a year ago.

Saudi's largest petrochemical maker Saudi Basic Industries dropped 1.8 percent and Al Rajhi Bank fell 0.6 percent.

Saudi stocks are easing after a strong start to the year, with the index still up 6 percent year-to-date.

Saudi Steel Pipes dropped 4 percent after reporting a net loss for its fourth-quarter compared with a profit a year earlier. The firm reported net loss after zakat and tax of 100.6 million riyals, compared with a profit of 15.7 million riyals a year earlier.

In Dubai, the index fell 0.1 percent, weighed down by financial stocks with the emirate's biggest lender Emirates NBD shedding 0.9 percent after three days of gains following a 10 percent rise in fourth-quarter net profit.

Air Arabia shed 1.2 percent. It said last week it had begun legal proceedings against former board member and Abraaj founder Arif Naqvi. The budget carrier has previously said it has an exposure of $336 million to collapsed private equity firm Abraaj. 

Qatar's index lost 0.3 percent with petrochemical maker Industries Qatar slipping 0.8 percent; HSBC had last week downgraded the stock to "reduce" from "hold" and cut the target price to 115 riyals from 125 riyals.

The Abu Dhabi index was down 0.2 percent with First Abu Dhabi Bank slipping 0.5 percent.

($1 = 3.6728 UAE dirham)

($1 = 3.7505 riyals)

(Reporting by Shakeel Ahmad in Bengaluru, editing by Larry King) ((shakeel.ahmad.thomsonreuters.com@reuters.net;))