UPDATE 1-China stocks suffer biggest one-day tumble since 2008, banks hammered
* CSI300 -7.7 pct, SSEC -7.7 pct, HSI -1.5 pct
* Margin trading penalties make brokerages plunge
* Bank, financial sub-indexes have record falls
* Tuesday's GDP data could hurt market - analyst
By Sue-Lin Wong
SHANGHAI, Jan 19 (Reuters) - China stocks suffered their biggest one-day percentage drop since the global financial crisis, dragged down by record tumbles for banks as authorities battled market speculation that fuelled a late 2014 spurt in share prices.
The two main indexes both fell 7.7 percent, their biggest losses since June 2008, and the plunge wiped out around $315 billion of market value from the Shanghai stock exchange, the country's biggest.
The CSI300 index of the largest listed companies in Shanghai and Shenzhen ended at 3,355.16 points and the Shanghai Composite Index at 3,116.35.
The China market was one of the world's best performers in 2014, thanks to surge of more than 40 percent in the last quarter. That was led by brokerages, which tumbled on Monday as authorities took steps to slash speculative trading. Continuación...