DUBAI, March 27 (Reuters) - Stock markets in the Gulf may soften slightly on Monday as U.S. stock index futures suggest a weak start on Wall Street and Asian bourses edge down, while oil prices barely move.

U.S. stock index futures are down 0.7 percent to a six-week low in heavy volume after U.S. President Donald Trump's failure to seal healthcare reform raised questions about his ability to push through tax cuts and fiscal spending to boost the economy.

Thin trading volumes in most of the Gulf in recent days - on Sunday, Saudi Arabia saw its thinnest trade since September - suggest there is little appetite among investors to build positions for now.

In Dubai, Emaar Malls confirmed that it was bidding up to $800 million to acquire e-commerce operator Souq.com. Its shares fell 0.8 percent on Sunday in response to a local media report revealing the bid, which could put Emaar Malls in a bidding war with Amazon.com ; sources said last week that the U.S. firm had agreed in principle to buy Souq.com.

Several Gulf stocks may see pressure as they go ex-dividend on Monday. In Saudi Arabia, they are large-cap dairy producer Almarai , United Wire Factories and Arriyadh Development , and in Abu Dhabi, RAK Properties , RAK Ceramics and Umm Al Qaiwain Cement.

(Reporting by Celine Aswad; Editing by Andrew Torchia) ((celine.aswad@thomsonreuters.com)(+9715 62247653)(Reuters Messaging: celine.aswad.thomsonreuters.com@reuters.net))