Investors were seen cautious amid US-Iran nuclear talks as the Qatar Stock Exchange (QSE) Tuesday fell 64 points and capitalisation eroded in excess of QR5bn.The domestic institutions were seen net profit takers as the 20-stock Qatar Index shed 0.56% to 11,362.59 points, although it touched an intraday high of 11,425 points.Six of the seven sectors reeled under net selling pressure in the main bourse, whose capitalisation melted QR5.45bn or 0.8% to QR676.75bn mainly on midcap segments.The foreign funds’ weakened net buying had its influence on the main market, whose trade turnover and volumes were on the decline.The Gulf institutions continued to be net sellers but with lesser intensity in the main market, which saw as many as 8,058 exchange traded funds (sponsored by AlRayan Bank and Doha Bank) valued at QR0.05mn trade across 11 deals.The foreign retail investors also continued to be bearish but with lesser vigour in the main bourse, which saw no trading of sovereign bonds.The Islamic index was seen declining faster than the main barometer of the main market, which saw no trading of treasury bills.The Total Return Index was down 0.14%, the All Share Index by 0.11% and the All Islamic Index by 0.15% in the main bourse.The telecom sector index declined 0.58%, real estate (0.49%), transport (0.31%), banks and financial services (0.17%), industrials (0.06%) and consumer goods and services (0.04%); while insurance gained 2.57%.As many as 21 gained, while 28 declined and five were unchanged.About 52% of the traded constituents were in the with major shakers in the main market being Woqod, QNB, Qatar National Cement, Dlala, Qatar German Medical Devices, Widam Food, Estithmar Holding, United Development Company, Ooredoo and Nakilat. In the juniour bourse, Techno Q saw its shares depreciate in value.Nevertheless, Qatar Cinema and Film Distribution, Qatar Insurance, QLM, Meeza, Gulf Warehousing, Mannai Corporation, Mazaya Qatar and Vodafone Qatar were among the movers in the main market.The domestic funds turned net sellers to the tune of QR10.04mn compared with net buyers of QR11.1mn on Monday.The foreign institutions’ net buying weakened substantially to QR16.05mn against QR32.46mn the previous day.The Gulf individuals’ net buying eased marginally to QR0.05mn compared to QR0.25mn on February 16.However, the Arab retail investors were net buyers to the extent of QR1.66mn against net sellers of QR5.57mn on Monday.The Qatari individuals turned net buyers to the tune of QR0.59mn compared with sellers of QR23.48mn the previous day.The Gulf institutions’ net selling weakened noticeably to QR6.93mn against QR8.86mn on February 16.The foreign individuals’ net profit booking shrank perceptibly to QR1.37mn compared to QR5.73mn on Monday.The Arab institutions had no major net exposure against net sellers to the extent of QR0.17mn the previous day.The main market saw 20% contraction in trade volumes at 115.63mn shares, 12% in value to QR377.23mn and 8% in deals to 22,178.In the venture market, a total of 0.14mn equities valued at QR0.29mn changed hands across 29 transactions.