Al Rajhi Bank and National Commercial Bank, which account for about a quarter of the index, were the biggest contributors to the Tadawul All Share Index's 1.7 percent loss.
Saudi Arabian stocks fell the most since December as investors locked in gains ahead of the holy month of Ramadan, when trading volumes in the kingdom typically decline.
Al Rajhi Bank and National Commercial Bank, which account for about a quarter of the index, were the biggest contributors to the Tadawul All Share Index’s 1.7 percent loss. About 160 stocks retreated as of 12:18 p.m. in Riyadh, the most on a closing basis since November.
“After a good rally in the banking sector, investors are taking a breather as most of the quarterly results are out now,” said Muhammad Faisal Potrik, the head of research at Riyad Capital.
“Al Rajhi posted record quarterly profit, but it’s also trading close to our target price” of 74 riyals, he said.
Its shares fell 2.1 percent to 73.6 riyals on Sunday.
Saudi Arabian equities declined as traders anticipated reduced liquidity during Ramadan, when Muslims fast from dawn until dusk. Most Muslims across the GCC work reduced hours throughout the month, which is set to begin this week.
The kingdom’s main stock gauge, among the world’s best performers this year, spent the entire month of April in oversold territory, helping to push to its estimated valuation to the highest since at least 2008, according to data compiled by Bloomberg.