PetroChina Co Ltd, China's largest oil explorer, will become fully tradable after unlocking 400 million non-tradable A-shares on Friday.

The last batch of PetroChina's non-tradable A-shares will be unlocked and become available for trading starting on Friday, signaling the Shanghai-listed company to be fully tradable on the market, said the nation's largest oil producer.

Regarding PetroChina's low share price at the moment, the unlocked 400 million shares will have a limited effect on the company's share price, the Beijing Business Today reported on Thursday citing unnamed source.

After four years of public trading, the share price of PetroChina slumped more than 80 percent to a bit above 7 yuan ($1.15) to date.

Public information showed PetroChina's profitability is improving. It turned out 29.77 billion yuan net profit in the third quarter this year, up 19.4 percent year-on-year. And its net profit from January to September also rose 9.6 percent to 95.29 billion yuan.