RIYADH  - Saudi stocks were almost flat in morning trade as investors awaited a decision from global index compiler MSCI on whether to include Saudi Arabia and its $526 billion bourse in its emerging market indexes at a review of its widely-tracked benchmark on Wednesday.

Other Gulf markets declined in largely muted trading as many investors are still on holiday for the Muslim festival of Eid.

The main Saudi index shed 0.15 percent by 0821 GMT.

The region's biggest stock market is up almost 14.5 percent so far this year and has outperformed Gulf markets in anticipation of the MSCI inclusion, which could trigger billions of dollars of inflows into Riyadh's Tadawul-listed stocks.

MSCI is due to announce the results of its Annual Market Classification Review around 2030 GMT. MSCI's gauges are used by investment funds worldwide, with some $1.7 trillion of active and passive money benchmarked against its EM indexes.

Blue chips dominated trading as investors bet on the leading Saudi companies that could join the MSCI index. Petrochemicals giant SABIC rose 0.3 percent and Almarai, the Gulf's largest dairy company, jumped 1.4 percent.

Other gulf markets were down amid low volumes, led by losses in Qatar, where the main index lost 1.3 percent in the first session after its Eid closure.

The index was mainly hit by a 4 percent fall in Qatar National Bank and a 0.7 percent decline in Masraf Al Rayan.

In Dubai, the index lost 0.3 percent, after falling almost 1.5 percent on Tuesday as concerns over trade tensions between the United States and China ricocheted through emerging markets.

The main drag came from banking and property shares, with Dubai Islamic Bank losing 1.0 percent and DAMAC and Emaar Malls EMAA.DU declining 1.3 percent and 0.5 percent respectively.

Abu Dhabi's index shed 0.4 percent with the United Arab Emirates' largest lender, First Abu Dhabi Bank (FAB), falling 1.2 percent and property developer Aldar losing 0.9 percent.

(Reporting by Marwa Rashad; Editing by Kevin Liffey) ((marwa.rashad@thomsonreuters.com; +966114632603 ; Reuters Messaging: marwa.rashad.thomsonreuters.com@reuters.net))