The GCC's largest exchange Tadawul closed at 6,216.67 points. Shares of Saudi Arabian Cooperative Insurance Company (SAICO), which hit a 2010-low at SR31.10, continued its rebound and surged 9.91% to SR36.60. Petrochemical giant and market indicator Sabic recaptured the level of SR90.00 (up 0.84%). The Business Optimism Index survey, which was done by National Commercial Bank (NCB) in association with Dun and Bradstreet South Asia Middle East Ltd (D&B), published today, reveals that the Kingdom's hydrocarbon sector optimism has increased substantially as the composite reading in the third quarter stands at 43 points as compared to 21 in the last quarter. Similar to other GCC markets, the number of shares ending flat increased in Riyadh, as 69 stocks gained, 51 decreased and 22 stood even as of the close of trading.