By Andrew Torchia

DUBAI, May 28 (Reuters) - Most Gulf stock markets fell in disappointment on Sunday after global oil producers agreed to extend cuts in output by nine months in an effort to prop up prices, while real estate developers boosted Egypt's index.

Last Thursday's oil output deal may put a floor under oil prices at around $50 a barrel for Brent crude LCOc1 , which could allow Gulf governments including Riyadh to spend a little more on economic growth this year.

"While the cuts will continue to trim headline GDP growth in the Gulf this year, the boost to oil export receipts should allow austerity to be eased further, supporting stronger growth in non-oil sectors," London-based Capital Economics said in a report.

But many in the markets had been hoping for stronger action by producers to push up oil prices, such as an agreement to deepen the production cuts or extend them further until mid-2018. Brent dropped by more than 4 percent to as low as $51.03 late on Thursday, though it then came back to $52.15.

Saudi Arabia's stock index .TASI , the most sensitive to oil prices, dropped 1.3 percent to 6,783 points, falling below technical support at 6,826-27 points, its lows in late March and May.

Daily trading volume was the lowest since September 2015, partly because of the start of the holy month of Ramadan, which traditionally thins market activity.

The market's decline was broad-based, with 161 stocks falling and just five rising. Petrochemical producer Nama Chemicals 2210.SE plunged its 10 percent daily limit.

In Dubai, the index .DFMGI slipped 1.0 percent in thin trade to 3,294 points, its lowest level since last November. Amusement park operator DXB Entertainments DXBE.DU , in a strong downtrend for the past month because of disappointing attendance at its parks, was the most heavily traded stock and fell a further 2.0 percent.

Builder Arabtec ARTC.DU , which has been languishing near multi-year lows, rebounded 2.5 percent as subscriptions to its planned capital increase ended.

Retail and restaurant investor Marka MARKA.DU initially rose but closed 1.2 percent lower after it appointed Benoit Lamonerie, whom it described as a 20-year veteran of retail and hospitality projects, as chief executive. The previous CEO resigned last December.

Qatar's index .QSI fell in early trade but closed 0.6 percent higher as Ezdan Holding ERES.QA recovered 0.7 percent. The stock had plunged 10 percent on Thursday after the property firm's shareholders gave preliminary approval to take it private.

In Egypt, the blue-chip index .EGX30 gained 0.9 percent as two real estate developers surged; Emaar Misr EMFD.CA jumped 9.1 percent in unusually active trade while Talaat Mostafa TMGH.CA added 2.0 percent. The broad EGX100 index .EGX100 fell 1.2 percent, however.

HIGHLIGHTS



SAUDI ARABIA



* The index .TASI sank 1.3 percent to 6,783 points.



DUBAI



* The index .DFMGI dropped 1.0 percent to 3,294 points.



ABU DHABI



* The index .ADI fell 0.5 percent to 4,496 points.



QATAR



* The index .QSI rose 0.6 percent to 10,123 points.



EGYPT



* The index .EGX30 gained 0.9 percent to 13,205 points.



KUWAIT



* The index .KWSE slipped 0.6 percent to 6,650 points.



BAHRAIN



* The index .BAX rose 0.2 percent to 1,317 points.

OMAN



* The index .MSI fell 0.3 percent to 5,387 points.

(Editing by Alison Williams) ((andrew.torchia@thomsonreuters.com)(+9715 6681 7277)(Reuters Messaging: andrew.torchia.thomsonreuters.com@reuters.net))