* Qatar sentiment still dampened by diplomatic dispute
* Saudi British Bank surges after Morgan Stanley upgrade
* Cityscape exhibition boosts some Dubai developers
* Abu Dhabi National Insurance Co up on stake sale hope
* Egypt climbs after lower inflation data
By Andrew Torchia
DUBAI, Sept 11 (Reuters) - Qatar's stock market sank to a 19-month low on Monday while other regional bourses were mixed in mostly quiet trade, although Saudi British Bank surged in Riyadh.
The Qatari stock index dropped 1.6 percent to 8,532 points, its lowest finish since January 2016, in a broad sell-off that saw declining stocks outnumber gainers by 27 to nine.
Qatar National Bank, the biggest lender, slid 2.0 percent and Qatar Gas Transport dropped 4.4 percent.
The market has been depressed by the diplomatic dispute between Qatar and its neighbours that erupted in early June, and after a phone call between leaders of Qatar and Saudi Arabia on Saturday, Riyadh accused Doha of "distorting facts" and suspended any further dialogue.
This suggested a resolution of the dispute might remain distant. Although wealthy Qatar is believed to have the financial resources to cope with its isolation, banks face higher funding costs as other Gulf states withdraw deposits.
The withdrawals have been pushing down the Qatari central bank's foreign reserves, which shrank $10.4 billion in June to $24.4 billion. The central bank usually releases each month's reserves data late in the following month but has not yet published July data; it has not given a reason for the delay.
In Saudi Arabia, the index gained 0.5 percent in rising trading volume as Nama Chemicals, which had surged 9.5 percent in unusually heavy trade on Sunday, added a further 2.1 percent to 21.90 riyals, though it pulled back from near technical resistance at its May peak of 23.22 riyals.
Saudi British Bank climbed 2.6 percent to 28.15 riyals after Morgan Stanley raised the stock to "overweight" from "equal-weight" and lifted its target price to 32.50 riyals from 31 riyals.
The Dubai index edged up 0.2 percent. Union Properties, the most heavily traded stock, added 0.9 percent and Deyaar gained 0.8 percent.
Direct sales of United Arab Emirates properties are being allowed at this year's annual Cityscape exhibition in Dubai for the first time in a decade. Deyaar said in a stock exchange statement on Monday that it was launching a new 1 billion dirham ($272 million) residential and hotel project at Cityscape.
In Abu Dhabi, the index slipped 0.2 percent but Abu Dhabi National Insurance Co (ADNIC) climbed 4.1 percent in thin trade. On Sunday, Reuters quoted sources as saying Abu Dhabi Investment Council was weighing a sale of its nearly 24 percent stake in ADNIC, with Allianz among groups showing initial interest in buying it.
In Egypt, the index climbed 0.6 percent in active trade after news that annual urban consumer price inflation dipped to 31.9 percent year-on-year in August from 33.0 percent in July. If inflation continues to drop, it could permit the central bank to ease policy late this year.
* The index gained 0.5 percent to 7,411 points.
* The index rose 0.2 percent to 3,654 points.
* The index fell 0.2 percent to 4,438 points.
* The index sank 1.6 percent to 8,532 points.
* The index climbed 0.6 percent to 13,533 points.
* The index edged up 0.01 percent to 6,927 points.
* The index fell 0.5 percent to 1,311 points.
* The index dropped 0.4 percent to 5,039 points. (Editing by Mark Potter)