* Saudi PetroRabigh surges on quarterly earnings
* SABIC falls back after gaining on Monday
* Dubai Investment mitigates Dubai's losses
* Banks drag down Qatar
* Zain falls again in Kuwait
By Aziz El Yaakoubi
DUBAI, Oct 31 (Reuters) - Saudi Arabia's stock market fell on Tuesday despite a big rebound by petrochemical company PetroRabigh, while Dubai Investments helped offset losses by real estate-related shares in that market.
The Saudi stock index dropped 0.2 percent as PetroRabigh's gain failed to bolster the petrochemical sector as a whole while banking and insurance stocks weighed heavily on the market.
PetroRabigh jumped 4.3 percent in its heaviest trade since May after reporting third-quarter net profit of 706 million riyals ($188.3 million) versus a year-earlier loss of 211 million riyals, with sales surging 43 percent.
The petrochemical sector in general was mixed, with Saudi Kayan rising 2.3 percent in heavy trade and National Petrochemical rising 1.6 percent. Saudi Basic Industries Corp, which had gained 0.6 percent on Monday after reporting a 10.7 percent rise in third-quarter net profit, above expectations, fell back 0.5 percent.
Most Saudi banks were down with Alinma Bank, the most heavily traded lender in the Saudi market, losing 0.2 percent and National Commercial Bank, the kingdom's largest lender, also falling 0.2 percent.
The Dubai index edged up 0.2 percent in modest trading volume as Dubai Investments rose 2.3 percent in heavy trade after reporting quarterly net profit attributable to shareholders of 350.4 million dirhams ($95.5 million), up from 334.4 million dirhams a year ago.
This offset drops by shares in Emaar Properties, down 0.6 percent, and builder Drake & Scull, which fell 2.0 percent.
Telecommunications company du DU> rose 0.6 percent after reporting quarterly net profit of 475.7 million dirhams, at the high end of analysts' estimates; SICO Bahrain had projected 453.5 million dirhams and EFG Hermes, 454.6 million dirhams.
Qatar's index edged down 0.4 percent because of banking shares; Islamic lender Masraf al Rayan dropped 1.8 percent and Qatar First Bank fell 0.3 percent.
In Kuwait, where the ruling emir accepted the resignation of the prime minister and his cabinet on Monday, the main index fell 0.7 percent. The ministers will continue important duties until a new cabinet is sworn in.
Many traders said the stock market was not expected to be affected much as such episodes are common in Kuwaiti politics. However, investment bank Exotix said in a report that the political instability could at least halt the Kuwaiti market's outperformance versus other Arab markets of the past 12 months.
Telecommunications firm Zain sank 4.1 percent, sliding for a third straight day after reporting on Sunday that net income fell 7 percent from a year ago in the third quarter, in line with analysts' forecasts.
Egypt's index added 1.0 percent to a fresh record high as property firm Amer Group Holding jumped 5.4 percent in heavy trade.
Jihad Azour, head of the International Monetary Fund's Middle East department, told Reuters this week that Egypt's economic reforms appeared to be working, with growth and revenues picking up in some areas.
He was speaking as an IMF delegation visited Cairo to review Egypt's reforms before providing another instalment of a three-year, $12 billion loan deal which the IMF agreed last November.
* The index fell 0.2 percent to 6,934 points.
* The index rose 0.2 percent to 3,636 points.
* The index climbed 0.5 percent to 4,480 points.
* The index fell 0.4 percent to 8,165 points.
* The index gained 1.0 percent to 14,342 points.
* The index dropped 0.7 percent to 6,514 points.
* The index edged up 0.02 percent to 1,277 points.
* The index rose 0.6 percent to 5,011 points. (Editing by Andrew Torchia and Ed Osmond)