Qatar's markets have also been hit by a decision to bar mainstream lenders from offering Islamic banking services
Qatar's index slumps to a two-week low, giving back early gains, with ongoing unrest in Bahrain and uncertainty over when Egypt's bourse will reopen spur risk aversion among investors.
Qatar Gas Transport Co (Nakilat) drops 1 percent, Barwa Real Estate loses 1.1 percent and Qatar National Bank falls 1.5 percent.
The latter is down 6.8 percent since the central bank ordered conventional lenders to halt their Islamic operations by the end of 2011. Few details have since emerged on how banks will comply and this uncertainty will weigh on shares, says Hani Girgis, assistant chief dealer at Dlala brokerage.
Qatar's index drops 0.7 percent to 8,761 points, slumping to its lowest level since Feb. 3. On Wednesday, it made its largest drop since Jan. 30, falling 1.8 percent
"After Egypt and now Bahrain, investors are a little afraid of what will happen in the region," says Girgis.
"Liquidity is low today after the selling wave yesterday. Investors are waiting for the Egypt exchange to re-open."
Bahraini police stormed a protest camp in a central Manama square early on Thursday, killing at least three people, and armoured vehicles rumbled through the capital as the government tried to quell three days of protest.
Bahrain's measure slips 0.3 percent to 1,463 points, a 10-day low, as four stocks trade.
Egypt has postponed the re-opening of the Cairo bourse for a third time. It was slated to resume trading on Sunday, having been shut since Jan. 27 as demonstrations paralysed the financial sector and led to the end of former president Hosni Mubarak's 30-year rule.
The exchange will now only reopen when banks are working properly.