BEIJING/SHANGHAI, March 18 (Reuters) - CITIC Securities Co , China’s biggest brokerage, reported on Thursday a 21.9% rise in profit in 2020, led by a strong gain in securities investment. Net profit for the 12 months ended December rose to 14.9 billion yuan ($2.29 billion) from 12.23 billion yuan a year ago despite the global COVID pandemic weighing on other sectors, the company said in a stock exchange filing. The results are largely in line with the preliminary results released in January. ($1 = 6.4998 Chinese yuan renminbi) (Reporting by Cheng Leng in Beijing and Engen Tham in Shanghai; Editing by Toby Chopra)