* Saudi NCB disappoints investors
* Alinma Bank loses 2.1 percent in heavy trade
* Mobily sinks 7.3 percent on Q3 loss
* Emaar falls another 2.3 percent
* Losses in Dubai mitigated by DSI
By Aziz El Yaakoubi
DUBAI, Oct 23 (Reuters) - National Commercial Bank (NCB) and telecom stocks dragged down Saudi Arabia's main index on Monday while Emaar Properties weighed on Dubai's stock market for the second day in a row.
The Saudi index fell 1.3 percent to 6,886 points on the back of the banking and insurance sectors, as NCB reported an 8.4 percent rise in third-quarter net profit, or around 5 percent below analysts' estimates. It fell 4.8 percent.
Bank Aljazira fell 1.0 percent, although it reported a 41 percent rise in third-quarter net profit to 228 million riyals. Alawwal Bank also sank 3.4 percent. Alinma Bank was the most heavily traded stock and lost 2.1 percent.
Most Saudi insurers also fell: Metlife AIG ANB Cooperative Insurance fell 1.7 percent and Malath Insurance lost 3.7 percent.
"NCB is one of the first stocks to affect the Saudi index, all the other banks and insurers just followed," said Jassim al Jubran, equity researcher at Aljazira Capital in Riyadh.
Saudi Arabia's Etihad Etisalat (Mobily) sank 7.3 percent after it reported a third-quarter loss on Monday, blaming a rule introduced last year requiring fingerprints be registered with SIM cards for shrinking the telecom market.
"Retail investors represent almost 90 percent of the market, so they tend to react immediately to the news," Al Jubran added.
The Dubai index lost 0.7 percent as Emaar fell another 2.3 percent, after losing 2.1 percent on Sunday, after it said it expects to sell 20 percent of its local property development unit Emaar Development LLC next month in an initial public offering.
Previously, Emaar had said it would offer up to 30 percent of the business, distributing funds raised as dividends to shareholders in the parent company. It did not say on Sunday why the sale was expected to be only 20 percent.
GFH Financial slipped 3.5 percent in heavy trade after rising on Sunday, when the United Arab Emirates securities regulator approved the listing of Bahrain's Khaleeji Commercial Bank, subject to approval by the Bahrain central bank.
GFH owns 47 percent of Khaleeji, and has long been aiming to list the bank in Dubai.
The losses in Dubai were mitigated by Drake & Scull International, which gained 2.5 percent and was the most heavily traded stock.
Qatar's index was down 0.5 percent after U.S. Secretary of State Rex Tillerson, who arrived in Doha on Sunday, said there was little chance of a swift breakthrough to resolve a blockade imposed on the Gulf state by Saudi Arabia and its Arab allies.
Qatar National Bank, the biggest bank in the Middle East, lost 1.1 percent. Ahli Bank sank 7.7 percent.
In Egypt, the index surged 1.2 percent as Juhayna Food Industries gained 4.2 percent after it reported a 12 percent rise in third-quarter consolidated net profit attributable to shareholders. In the first half of the year, its profits had dropped.
* The index fell 1.7 percent to 6,886 points.
* The index dropped 0.7 percent to 3,618 points.
* The index was flat at 4,499 points.
* The index fell 0.5 percent to 8,158 points.
* The index rose 1.2 percent to 13,870 points.
* The index edged down 0.4 percent to 6,622 points.
* The index added 0.3 percent to 1,287 points.
* The index dropped 0.3 percent to 5,033 points. (Reporting By Aziz El Yaakoubi, editing by Larry King)