* Egypt underperforms global emerging market index
* But exchange data shows foreigners are net buyers
* Broad market fares better than blue-chip index
* Saudi's Mobily hit by regulator's penalties
* United Electronics rises after strong earnings
By Abinaya Vijayaraghavan
Oct 8 (Reuters) - Egypt's blue-chip stock index plunged 3.6 percent on Monday to its lowest level in 12 months, dragged down by weakness in emerging markets and margin calls among local investors, while banking shares boosted Saudi Arabia.
Twenty-nine of 30 stocks in the Egyptian index fell. It has fallen 15 percent since the end of August, leaving it down 9.4 percent year-to-date. The broader EGX100 index fared better on Monday, losing only 1.9 percent.
Egypt's market far underperformed the MSCI index of emerging market stocks, which was down nearly 1 percent. Among big blue-chip losers were tobacco firm Eastern Co, down 4.9 percent.
Exchange data showed Monday's selling was heavily concentrated among local investors, who were hit by margin calls. Non-Arab foreign investors were net buyers by a considerable margin, the data showed.
"It is a mixture of both emerging market weakness and margin trading, and the closure of some margin trades," said Radwa El-Swaify, head of research at Pharos Holding said.
Turmoil in emerging markets has fuelled concern about possible capital outflows from Egypt and depreciation of the pound currency. But many foreign fund managers say they remain long-term positive on the market because of an improving underlying economy.
Khaled Abdel Majeed, managing partner at London-based asset manager MENA Capital, said Monday's drop was due to a combination of profit-taking and emerging market weakness, but he was confident the slide would not continue.
Memphis Pharmaceuticals shed 9.5 percent after its first-quarter loss widened year on year.
In Saudi Arabia, the index rose 0.6 percent with Al Rajhi Bank up 1.6 percent and Samba Financial Group gaining 1.6 percent.
Telecommunications firm Mobily fell 2.3 percent after saying the regulator had ordered it to suspend sales of some products to new customers because it had failed to hire enough Saudi citizens at the top of the company.
United Electronics Co was up 2.0 percent after reporting a quarterly net profit of 30.9 million riyals ($8.2 million), up from 26.1 million riyals last year, while revenues also climbed.
The Gulf's largest dairy company, Almarai Co, dropped 2.9 percent after reporting a fall in third-quarter profit on Sunday.
Advanced Petrochemical extended losses, falling 2.1 percent after reporting a slight fall in quarterly net income, also on Sunday.
Dubai's index closed 0.6 percent lower after bank stocks reversed early gains. Emirates NBD fell 1.6 percent.
Al Ramz Corp plunged 6.1 percent after saying it had divested its 17.8 percent stake in insurer Takaful Emirates having achieved its targeted return. SAUDI ARABIA * The index rose 0.6 percent to 7,939 points. DUBAI * The index fell 0.6 percent to 2,775 points. ABU DHABI * The index inched up 0.3 percent to 5,003 points. QATAR * The index slipped 0.3 percent to 9,820 points. KUWAIT * The index was up 0.04 percent to 5,309 points. BAHRAIN * The index rose 0.1 percent to 1,325 points. OMAN * The index shed 0.2 percent to 4,505 points. EGYPT * The index fell 3.6 percent to 13,604 points. (Editing by Andrew Torchia and John Stonestreet)