By MERRIT KENNEDY

CAIRO — Egypt’s stock market plunged by 22 billion Egyptian pounds (just over $3 billion) in a single day of trading Sunday as low oil prices dragged down regional economies.

The EGX30 index closed 5.23 percent lower, with 170 stocks declining and just five showing gains.

Yasser Rashad, a stock broker, said there was an immediate dip at the start of the session–“an indication that there has been an intention over the weekend…to sell as soon as the today’s session began, out of fear of the stocks continuing to drop this week.” á

Wael Ziada, head of research at EFG Hermes, said the drop is a knock-on effect caused by the steep decline in oil prices, which have decreased by nearly half since late June. “These markets are correlated in terms of their performance because the investor base intersects.”

Going forward, the impact of declining oil prices on Egypt’s economy is less clear. Egypt is a net importer of oil, therefore “we should benefit from the decline in oil prices,” said Ziada.

However, Egypt relies heavily on aid from Gulf countries to buoy its economy. Any net benefit from the decline in oil prices is “assuming that whatever aid plans from the GCC market will flow uninterrupted, but this is one thing that you don’t know for a fact,” Ziada added. The Gulf Cooperation Council includes Saudi Arabia, Kuwait, the United Arab Emirates, Qatar, Bahrain and Oman.

Saudi Arabia, Kuwait and the United Arab Emirates pledged billions of dollars in aid to Egypt’s military-backed government after last year’s overthrow of Islamist President Mohammed Morsi.

A Bank of America/Merrill Lynch Global Research report published last week said “although GCC support may be somewhat less forthcoming at current oil prices, enough is likely to be provided to muddle through for now.”

Last month, an International Monetary Fund official said that Egypt’s economy had begun to recover after nearly four years of political turmoil. The EGX30 index has shown overall gains of 28.49 percent so far this year.

The government aims to attract investment by hosting a three-day international economic conference in March. It recently slashed fuel subsidies and is pursing revenue-enhancing measures aimed at deficit reduction.