Inflation worries and expected higher interest regime in the US on account of latest job data had their reflection on the Qatar Stock Exchange (QSE), which Monday saw its key index plummet as much as 185 points and capitalisation erode more than QR10bn.The foreign institutions were seen increasingly net profit takers as the 20-stock Qatar Index rose 1.78% to 10,219.69 points, although it touched an intraday high of 10,408 points.An across the board selling – notably in the banking and telecom counters -- was visible in the main bourse, whose capitalisation eroded QR10.18bn or 1.68% to QR600.42bn on the back of large and midcap segments.As much as 96% of the traded constituents were in the red in the main market, which saw a total of 0.01mn exchange traded funds (sponsored by AlRayan Bank and Doha Bank) valued at QR0.06mn change hands across seven transactions.The Gulf institutions’ weakened net buying had its effect on the main bourse, whose trade turnover and volumes were on the rise.The Islamic index was seen declining slower than then the other indices in the main bourse, which saw no trading of treasury bills.However, the local retail investors were seen bullish in the main market, which saw no trading of sovereign bonds.The Total Return Index shed 1.78%, the All Share Index by 1.67% and the All Islamic Index by 1.64% in the main market.The telecom sector index tanked 2.54%, banks and financial services (1.95%), transport (1.55%), industrials (1.37%), consumer goods and services (1.36%), real estate (0.47%) and insurance (0.16%).Major losers in the main market included Industries Qatar, Ooredoo, Qatar Islamic Bank, QIIB, Ezdan, Qatari Investors Group, Widam Food, Alijarah Holding, Mesaieed Petrochemical Holding, Gulf Warehousing, Nakilat, Milaha and Salam International Investment. In the junior bourse, both Al Mahhar Holding and Techno Q saw their shares depreciate in value.Nevertheless, Doha Insurance and Vodafone Qatar were the two gainers in the main market.The foreign institutions’ net selling increased significantly to QR71.34mn compared to QR8.82mn on January 12.The Gulf institutions’ net buying weakened noticeably to QR1.65mn against QR11.72mn the previous day.However, the Qatari individuals turned net buyers to the tune of QR40.47mn compared with net sellers of QR0.83mn on Sunday.The domestic institutions were net buyers to the extent of QR13.4mn against net sellers of QR0.53mn on January 12.The Arab individuals turned net buyers to the tune of QR7.67mn compared with net profit takers of QR0.09mn the previous day.The foreign retail investors were net buyers to the extent of QR7.14mn against net sellers of QR0.19mn on Sunday.The Arab institutions turned net buyers to the tune of QR0.58mn compared with no major net exposure on January 12.The Gulf individual investors were net buyers to the extent of QR0.43mn against net sellers of QR1.27mn the previous day.Trade volumes in the main market soared 60% to 141.17mn shares and value by 91% to QR415.24mn on more than doubled transactions to 17,257.The venture market saw trade volumes grow six-fold to 0.54mn equities and value by more than five-fold to QR1.34mn on more than doubled deals to 33.