PetroChina, the country's biggest oil and gas producer, is weighing a plan to carve out its marketing and trading business and seek a separate listing, people with knowledge of the matter said.

China National Petroleum Corporation, the state-owned parent of PetroChina, has asked external consultants to provide proposals on the feasibility of such a plan. A surge in oil prices earlier this year prompted the Beijing-based firm to consider monetizing the business, the people said.

China Tourism Group Duty Free is telling prospective investors it plans to price its Hong Kong share sale in the upper half of its marketed range, according to people familiar with the matter, in what could be this year's biggest listing in the city.

The Shanghai-traded company is offering 102.8 million shares in Hong Kong at HK$143.50 to HK$165.50 each. At the top price, it would raise HK$17 billion.