RIYADH  - Gulf stock markets were mostly little changed early on Thursday, but Kuwait climbed on expectations for passive fund inflows as it joins the FTSE Russell emerging market index.

Kuwait's blue-chip index climbed 1.1 percent, with National Bank of Kuwait gaining 1.3 percent to its highest intra-day level in more than seven years. Kuwait Finance House was up 1.5 percent and Boubyan Bank added 3.0 percent.

The main market index, which includes smaller stocks, was up just 0.2 percent.

Kuwait will join the Russell index in two phases, on Sept. 24 and Dec. 24, and Kuwaiti stocks in the index can expect flows of passive funds on the previous day. Arqaam Capital estimates passive inflows in both phases combined will reach $1 billion.

Saudi Arabai's index was flat although Saudi Basic Industries rose 1.2 percent. Rights to MedGulf's share issue were again heavily traded, jumping 11.9 percent, while the underlying stock gained 5.2 percent.

Dubai rose 0.3 percent, with 21 stocks advancing and six declining.

(Reporting by Marwa Rashad, writing by Andrew Torchia, editing by Larry King) ((marwa.rashad@thomsonreuters.com; +966114632603 ; Reuters Messaging: marwa.rashad.thomsonreuters.com@reuters.net))