(Updates with the stock exchange's confirmation)
NAIROBI, Sept 1 (Reuters) - Kenya's stock exchange halted trading briefly midway through Friday's session after blue chip shares plummeted following the Supreme Court's decision to annul the result of the Aug. 8 presidential election.
Trading restarted at 1000 GMT, Nairobi Securities Exchange chief executive Geoffrey Odundo told Reuters.
"When there is a movement in the market beyond a certain limit, we have to stop trading to allow the market to process the information," Odundo said.
He said shares had fallen by the 10 percent limit, which requires a halt.
East Africa's biggest economy has a history of disputed polls. The court decision to cancel the result, the first of its kind in Kenya's history, sets up a new race for the presidency between Uhuru Kenyatta and veteran opposition leader Raila Odinga.
Real time data is usually not available for the market apart from for individual stocks.
Telecoms operator Safaricom, the biggest company by market cap, fell 4.9 percent to trade at 24.00 Kenyan shillings ($0.2328) per share, traders said.
"No one likes uncertainty especially if the uncertainty period is as long as 60 days," said Ken Minjire, head of securities at Nairobi-based Genghis Capital.
Kenyatta and Odinga will face off in a runoff election within 60 days according to the constitution.
The shilling had weakened 0.4 percent immediately following the court's ruling to 103.20/40. ($1 = 103.1000 Kenyan shillings) (Reporting By Duncan Miriri and Maggie Fick; Editing by Hugh Lawson)