* Saudi's Al Tayyar slumps after denying Indonesia deal report
* Dubai falls below technical support
* Banks are main drag on Abu Dhabi
* Juhayna and Talaat Mostafa shine in Cairo
By Celine Aswad
DUBAI, March 5 (Reuters) - Most Gulf bourses fell in light trade on Sunday, with Dubai's index dropping below technical support while Egypt continued to firm on the news that authorities would tax stock market transactions only gradually.
Saudi Arabia's index lost 0.7 percent, with about 70 percent of stocks dropping. Most petrochemicals shares fell, including a 1.8 percent decline for Saudi Kayan Petrochemical .
Tourism company Al Tayyar Travel slumped 5.1 percent in heavy trade after it denied local media reports that it had signed 5 billion riyals ($1.3 billion) of deals with Indonesian companies for religious tourism.
Its shares had jumped by more than 9 percent on Thursday.
Al Sagr Cooperative Insurance dropped 4.2 percent after the board recommended a cash dividend for 2016 of 2 riyals per share, unchanged from the previous year.
Dubai's index lost 1.1 percent to 3,543 points, falling below minor technical support on its February low of 3,551 points. The index has stronger support at the late December lows around 3,500 points.
Theme park operator DXB Entertainments, the most active stock, retreated 2.1 percent to a one-year low of 1 dirham.
In neighbouring Abu Dhabi, banks weighed on the index , which fell 0.7 percent.
National Bank of Abu Dhabi (NBAD) lost 2.3 percent to 10.45 dirhams and First Gulf Bank slipped by 0.4 percent to 13.85 dirhams. The pair are due to merge on April 1.
SICO Bahrain expects the new bank to trade at a "demanding" price-to-book ratio - a widely used metric to value banks against peers. SICO gave NBAD a "sell" rating with a target price of 10.5 dirhams and has cut FGB to "sell" from "neutral" with a target of 13.2 dirhams.
The Kuwaiti index added 0.6 percent on the back of a 1.6 percent rise for Kuwait Finance House and a 1.5 percent gain by Burgan Bank in unusually heavy trade. Burgan's dividend yield is 5.5 percent, at the higher end of yields offered by lenders in the region.
Egypt's index added a further 1.5 percent, having climbed by 2.6 percent on Thursday on news that the Finance Ministry would propose only a gradual introduction of a stamp duty on transactions to minimise the impact on trade.
Juhayna Food, which has yet to report fourth-quarter earnings, jumped 5.7 percent.
Real estate developer Talaat Mostafa extended gains with a 2.9 percent jump, having risen by 3.5 percent on Thursday after its annual earnings statement.
Qatar's stock market was closed for a public holiday.
* The index fell 0.7 percent to 6,968 points.
* The index lost 1.1 percent to 3,543 points.
* The index dropped 0.7 percent to 4,565 points.
* The index rose 1.5 percent to 12,500 points.
* The index added 0.6 percent to 6,805 points.
* The index slipped by 0.1 percent to 5,809 points.
* The index added 0.1 percent to 1,343 points.
Editing by Andrew Torchia; Editing by David Goodman