** Hong Kong shares of Guotai Haitong Securities 2611.HK jump 4.5% to HK$9.94, on track for biggest one-day pct gain since February 26

** Co estimates Q1 net profit to rise 350%-400% y/y

** Shanghai listed stock 601211.SS rises 3.7% to 16.01 yuan, on course for the biggest one-day pct gain since January 24

** Hang Seng Composite Index tracking financials stocks .HSCIF little changed, while Hang Seng Index .HSI climbs 1.3%

** YTD, Guotai Haitong's HK stock down 11.2%, Shanghai shares have fallen 17.2%

(Reporting by Donny Kwok)

((donny.kwok@thomsonreuters.com))