Lender QNB edged 0.5 percent higher. The first major regional lender to report earnings, the bank is closely watched for indications of the sector's performance.
The bank edged past estimates with second-quarter profit of 1.8 billion riyals ($494.8 million).
Qatar's index eased 0.1 percent to 8,492 points, its first decline in eight sessions. Losers outnumbered gainers 17 to three.
In Egypt, investors fear the planned protests may prolong instability in the wake of an uprising earlier this year.
Commercial International Bank, Egypt's biggest listed bank, dropped 2.6 percent and Orascom Telecom 2.3 percent. Ezz Steel shed 4 percent.
"Investors are terrified about Friday," Heba Saleh of Arab Finance Brokerage said. "The idea of mass protests and what may happen after that in the stock market in general is driving these fears," she added.
Orascom Construction Industries dropped 2.3 percent despite news the firm had secured infrastructure work in Saudi Arabia worth $450 million.
"The market discounts any good news," Saleh said. "The stock market is going down in general because of wider sentiment."
The benchmark index fell 2.2 percent to 5,321 points.
Elsewhere, UAE markets ended lower in thin trade and second-quarter earnings will do little to rouse them from their slumber.
In Dubai, Dubai Financial Market fell, courier Aramex slid 1.1 percent and Dubai Islamic Bank lost 1.5 percent.
The emirate's index dropped 0.4 percent to 1,552 points, its first decline in five sessions.
"We are in an uneventful pocket right now," said Akram Annous, MENA strategist at Al Mal Capital.
"I wouldn't be expecting anything in terms of surprises in Q2 earnings, with a solid performance out of petrochemicals and some signs of a pick-up in credit growth in the UAE and Saudi Arabia, which could get some people encouraged," added Annous.
Abu Dhabi's index fell 0.5 percent to 2,717 points, easing from Tuesday's two-week high.
In Saudi Arabia, investors booked profits in blue chips ahead of the weekend and pushed the index into the red. The Tadawul All-Share Index (TASI) closed 0.22 percent down at 6,612.46 points.
Second-quarter earnings are expected to kick off soon, and fresh funds are waiting on the sidelines until results give investors guidance to start buying.
"Over the next few months, we should see a steady inflow of foreign money - economic fundamentals in Saudi Arabia are pretty solid," said Paul Gamble, head of research at Jadwa Investment.
"There were net outflows of foreign money from the Saudi market last month — that may have been because of general risk aversion given what's happening in Greece and global economy."
Saudi Telecom Co. eased 0.3 percent and Saudi Arabian Fertilizers Co. (SAFCO) fell 2 percent.
The Kuwait measure slipped 0.08 percent to 6,209 points and the Omani index advanced 0.04 percent to 5,952 points.
The Bahraini index climbed 0.09 percent to 1,318 points.
