Clifford Chance (CC) and Allen & Overy (A&O) have landed lead roles on two key Hong Kong initial public offerings (IPOs), working opposite US outfits Davis Polk & Wardwell and Kirkland & Ellis respectively.

The planned listings of state-owned brokerage China Galaxy Securities Co and Sinopec Engineering (Group) Co, a wholly owned subsidiary of Asia's biggest oil refiner, Beijing-based Sinopec Group, are said to be the biggest IPOs in Hong Kong so far this year.

The companies reportedly received approval from the Hong Kong Stock Exchange last week, and are expected to begin pre-marketing later this month.

CC and Davis Polk are acting on the $1bn-$1.5bn (£653m-£980m) IPO of China Galaxy Securities, the country's seventh-largest brokerage, with the magic circle firm representing the underwriters and the US firm acting for the issuer.

CC's team is led by corporate partner Tim Wang in Beijing, while Davis Polk's efforts are being jointly managed by Hong Kong corporate partners Bonnie Chan and Antony Dapiran and Beijing-based partner Li He, who is advising on US aspects.

A group of 16 banks are arranging the IPO, which is just short of a record 17 appointed by the state owned People's Insurance Company (Group) of China (PICC Group) for its own $3.5bn (£1.87bn) listing, which closed at the end of last year.

Those cited in media reports include China Galaxy International, Goldman Sachs and JP Morgan, in addition to ABC International, BoCom International, Bank of America Merrill Lynch, Credit Suisse Group, CCB International, Citigroup, Deutsche Bank AG, Haitong Securities International, HSBC Holdings PLC, ICBC International, Nomura, Standard Chartered and UBS.

Chinese outfits assisting on the deal include Grandall Law Firm and Commerce & Finance Law Offices.

Meanwhile, A&O and Kirkland are advising on the $1.5bn-$2bn (£980m-£1.3bn) IPO of Sinopec Engineering, with the magic circle firm acting for the issuer and the US firm representing the banks.

A&O's team is being led by Vivian Yiu in Hong Kong, whilst Kirkland has turned to former Skadden capital markets partner Dominic Tsun to lead its team out of Hong Kong.

Sponsors and joint bookrunners include Citic Securities International, JP Morgan and UBS, alongside Bank of America Merrill Lynch, CICC, Citigroup, Deutsche Bank, Goldman Sachs, Haitong Securities International and HSBC.

Last year was one of the worst on recent record for Hong Kong listings, with the city's bourse dropping from the world number one for three years running to fourth place, according to Dealogic. Partners were hoping for an uptick in 2013, but have continued to feel the pressure of a dearth in new offerings.

The biggest listing so far this year has been the $398m (£253m) IPO of China's biggest aluminium producer Chinalco Mining Corp, with Slaughter and May, Paul Hastings and Simpson Thacher & Bartlett among those advising on the deal.

Last year's largest IPO was by PICC Group, on which Slaughter and May and Davis Polk picked up lead advisory roles alongside Sullivan & Cromwell.

Related: Slaughters, Simpson Thacher among firms on $398m Chinalco HK listing.