Small-time players need not apply when the Saudi Arabian stock market opens to foreign investment on June 15, according to regulations released on Monday.
The Capital Market Authority (CMA) said institutional investors must have a minimum of 18.75 billion riyals ($5 billion, 4.5 billion euros) under management to invest directly in the bourse, Bloomberg News reported.
CMA, the chief regulator, reserved the right to lower the limit to 11.25 billion riyals.
It also restricted foreign ownership of a single stock to 49 percent, Bloomberg News said.
The CMA previously announced that individual investors will be excluded.
Until now, only companies registered in Saudi Arabia or the five other Gulf Cooperation Council nations could buy and sell stock directly on the Tadawul All-Shares Index, the largest Arab bourse.
Foreigners could trade indirectly through Saudi and GCC-based investment funds.
The bourse has a market capitalisation of more than $500 billion.
"Opening up the market is likely to lead to inclusion into the MSCI emerging market index by mid-2017, with as much as $40-50 billion of total foreign inflows," Saudi-based Jadwa Investment said last month.