DUBAI - Car insurance and rental companies were some of the chief gainers in a generally weak Saudi Arabian stock market early on Wednesday after news that women would be allowed to drive.

King Salman on Tuesday issued a royal decree lifting the driving ban; it will be implemented by June 24, 2018, according to state news agency SPA.

There are about 10 million women, including foreigners, over the age of 20 living in the kingdom. Shares in all of the 30 listed insurers that provide auto insurance rose, led by Alrajhi Co for Cooperative Insurance, which surged 9 percent.

Car rental company United International Transportation jumped 6.0 percent.

The main Saudi stock index, however, fell 0.4 percent in the first 45 minutes of trade as investors worried that index compiler FTSE might issue a negative decision when it determines whether to upgrade Riyadh to emerging market status at the end of this month.

Most blue chips, which analysts believe would become members of FTSE's Secondary Emerging Market Index in the event of a positive decision, were weak, including dairy maker Almarai, which fell 0.2 percent.

In Doha, the index fell 0.6 percent, snapping a six-day winning streak. All but three of the 20 most valuable shares fell, including Qatar Insurance, which declined 1.4 percent.

In the United Arab Emirates, Dubai's index rose 0.4 percent as Emaar Properties added 0.9 percent. The Abu Dhabi index was down 0.1 percent.

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