* Saudi petchems hold up well after slide on budget

* But margin calls hit speculative shares hard

* Almarai tumbles after forecasting higher costs

* Egypt sinks as it reopens after holiday

* Qatar underperforms UAE bourses

By Andrew Torchia

DUBAI, Jan 10 (Reuters) - A sell-off of small-cap speculative stocks pulled Saudi Arabia's stock market down on Sunday, while Egypt dropped in response to weak global equities and concern about risks to the Chinese economy. Most Gulf markets were subdued.

The Saudi index, which had plunged 9.9 percent last week as oil prices slid, fell a further 2.2 percent to 6,091 points, its lowest level since November 2011.

In contrast to last week, Saudi petrochemical shares help up well, showing some resilience after a slide triggered by rises in the price of natural gas feedstock in the 2016 Saudi state budget. Saudi Basic Industries rebounded 1.1 percent.

But margin calls triggered by recent losses hit smaller, speculative stocks hard. National Agricultural Development , for example, plunged 10.7 percent.

"It was an automatic response...People were not able to cover margin calls because of the prior losses," said one Riyadh fund manager.

Major lender Al Rajhi Bank sank 2.7 percent and dairy firm Almarai plunged 10 percent after it said utility price increases featured in the budget, as well as new crop-growing restrictions, would increase its costs by 500 million riyals ($133 million) in 2016.

Underlining expectations for an economic slowdown in Saudi Arabia, retailer Jarir Marketing, a top play on the kingdom's consumer demand, fell 1.8 percent. It posted a fourth-quarter net profit flat to the previous year, in line with analysts' estimates.

Egypt's main index sank 2.0 percent; the market was closed for a holiday on Thursday as other regional markets fell sharply.

Commercial and International Bank slid 2.2 percent. President Abdel Fattah al-Sisi said on Saturday that the banking sector would inject 200 billion Egyptian pounds ($25 billion) to support small and medium-sized businesses. The scheme may involve fresh liquidity provision by the central bank to commercial banks, but it is unclear whether it could expose banks' balance sheets to fresh risks.

The economy continues to struggle; business activity in Egypt shrank for the third month in a row in December, a corporate purchasing managers' survey showed on Sunday.

In a report on world economies at the end of last week, the World Bank cut its forecast for Egypt's gross domestic product growth in 2016 to 4.1 percent from its previous prediction, made six months ago, of 4.7 percent; it lowered its forecast for 2017 to 4.6 percent from 4.8 percent. It estimated growth in 2015 at 4.0 percent.