(Corrects last week's yield on 364-day bills to 14.839 pct (not 14.990)
CAIRO, June 13 (Reuters) - Yields on Egyptian treasury bills remained relatively steady at an auction on Thursday with the central bank selling all that was on offer despite jitters in other Egyptian markets ahead of anti-government protests planned for later this month.
The protests along with fuel shortages and a warning on the difficulties of getting money out of the country sent the stock market's main index on Wednesday to its lowest close in almost a year.
Opposition parties and activists have called the mass demonstrations for June 30 to mark the first-year anniversary of the election of Muslim Brotherhood candidate Mohamed Mursi as president.
On Thursday, the Egyptian pound weakened on the black market and the country's debt insurance costs hit their highest level since October 2008, and on Wednesday the MSCI raised concerns about getting money out of Egypt.
Some traders said that T-bill purchases by state-owned banks appear to be keeping yields from rising, but another trader said the market had already factored the negative political and economic news in.
The average yield on 3 billion Egyptian pounds ($429 million) of 182-day treasury bills rose to 14.434 percent from 14.379 percent at last week's auction.
The yield on 4 billion pounds of 364-day treasury bills climbed to 14.877 percent from 14.839 percent last week, the central bank said.
The stock market regained some of Wednesday's losses on Thursday. ($1 = 6.9913 Egyptian pounds) (Reporting by Patrick Werr; Editing by Toby Chopra)