* Union Properties comes off low, expects no more provisions
* Dubai's Marka hit by earnings, GFH by share dilution
* But Emaar Properties firm after in-line earnings
* Investment Holding continues post-listing slide in Qatar
* Telecom Egypt rises on earnings
DUBAI, Aug 15 (Reuters) - Middle Eastern stock markets sagged again on Tuesday because of a mediocre economic outlook, with a shock loss at a real estate developer weighing on Dubai and Egypt dropping for a sixth straight day.
Union Properties sank 4.3 percent to 0.82 dirham after it reported a 2.29 billion dirham ($624 million) net loss for the second quarter, although the stock came well off its intra-day low of 0.77 dirham. It accounted for over a third of Dubai's trading volume.
The company said it was taking big provisions to cover past accounting errors related to its booking of a 503 million dirham gain on a plot of land at Dubai's Motor City.
The errors were discovered as a new board and senior management, appointed in May, conducted an investigation of accounting practices dating back to 2013, the company said. Its chairman later told Al Arabiya television that he did not expect to take further provisions in coming quarters.
Dubai's stock index dropped 0.2 percent. It was buoyed by a 0.1 percent gain by Emaar Properties, the biggest developer, which reported a 14.4 percent increase in second-quarter profit, in the middle of analysts' forecasts.
But restaurant and retail investment firm Marka sank 5.1 percent to a record low after reporting a second-quarter loss attributable to shareholders of 126 million dirhams ($34.3 million) versus a year-ago loss of 18.7 million dirhams.
GFH Financial fell 3.3 percent, bringing its losses over two days to 12.9 percent. The company said it had completed the acquisition of a $1.2 billion infrastructure portfolio in Africa and the Middle East, funded by a $315 million capital increase that took issued and paid-up capital to $975 million - a big dilution for minority shareholders.
Abu Dhabi's index edged down 0.2 percent although Eshraq Properties, which had been trading at its lowest levels this year, rebounded 1.2 percent in its heaviest volume for five weeks.
Saudi Arabia's index declined 0.3 percent. Insurer MedGulf, which has been falling sharply this week after reporting a big second-quarter loss, slid a further 2.9 percent. Wafa Insurance, which earlier this month reported lower quarterly profit, fell 3.1 percent.
In Qatar, the index dropped 0.6 percent as Gulf Warehousing lost 1.7 percent. Investment Holding Group , which tumbled 13 percent from its initial public offer price on Monday as it listed on the market, fell a further 1.7 percent.
Egypt's index slid 0.3 percent to 13,102 points, confirming a break below its July low of 13,261 points and support on its 100-day average, now at 13,171 points. A head & shoulders pattern formed by the highs and lows since June, and triggered this week, points down to about 12,650 points.
The broader EGX100 dropped 1.6 percent. Financial services firm Pioneers Holding lost 3.5 percent and blue chip Orascom Telecom Media fell 1.5 percent.
Telecom Egypt gained 1.1 percent, however, after reporting that second-quarter consolidated net profit after tax jumped 22 percent year-on-year to 1.27 billion Egyptian pounds ($72 million).
* The index declined 0.3 percent to 7,103 points.
* The index fell 0.2 percent to 3,580 points.
* The index dropped 0.2 percent to 4,471 points.
* The index slipped 0.6 percent to 9,134 points.
* The index slid 0.3 percent to 13,102 points.
* The index fell 0.2 percent to 6,844 points.
* The index lost 0.6 percent to 1,312 points.
* The index dropped 0.8 percent to 4,939 points. (Reporting by Andrew Torchia; editing by Mark Heinrich)