Linklaters and Jenner & Block have won roles as General Motors this week increased the number of shares on offer in its landmark initial public offering (IPO), reports The Am Law Daily.

The car maker, which is being advised by US firm Jenner, has responded to strong market demand by expanding the IPO by 31%, helping the company to raise $23.1bn (£14.4bn) in what could be the largest IPO ever.

GM's main joint venture partner in China, SAIC Motor Corp, has bought a 1% stake in the automaker for nearly $500m (£311m), paying $33 (£21) a share.

Linklaters corporate partners Scott Sonnenblick and Jeffrey Schmidt are advising SAIC on the transaction along with corporate counsel Richard Gu and Jeff Zhang. SAIC, a long-term client of the firm, is partnered with GM in China and India.

According to a prospectus filed with the US Securities & Exchange Commission, longstanding GM adviser Jenner has so far received $6.5m (£4m) for its work on the IPO. Jenner corporate partners Joseph Gromacki, William Tolbert and Brian Boch are serving as lead issuer's counsel for GM.

As a result of the IPO, GM will see the stake in the company held by the US Treasury Department cut from 61% to 26%, as the company begins the process of returning to profitability.

US firm Davis Polk & Wardwell has also taken a role on the IPO, with corporate partners Richard Drucker and Sarah Beshar advising the underwriters led by Bank of America Merrill Lynch, Citigroup, JPMorgan Chase, and Morgan Stanley.

The Am Law Daily is a US affiliate title of Legal Week.