Wu was managing partner of Ernst & Young's China business in 1996. He became deputy chairman of the firm in 1998 and chairman in 2000. He left the firm in 2005.
New China Hong Kong Group
Wu was appointed to the first board of directors of New China Hong Kong Group Limited in 1992, resigning in February 1993 to serve on its Executive Committee and act as Financial Advisor thereafter until its collapse in early 1999 with HK$1.5 billion in unpaid creditors. At the same time as being Vice-Chairman of Ernst & Young, the company's auditor, Wu, in addition to being a member of the company's executive committee, was an authorised signatory to 13 of its bank accounts, had significant personal dealings with its subsidiaries and lent money to it.
Public appointments and politics
From 1997 to 2001, Wu was a member of the Hospital Governing Committee of the Pamela Youde Nethersole Eastern Hospital, Hong Kong. After three years as a member of the Hospital Authority of Hong Kong's Audit Committee and four years as chairman of its Finance and Tender committees, Wu was appointed chairman of the Authority on 7 October 2004, a post he held for the following nine years. In 2004, Wu was a member of the Disciplinary Panel of the Hong Kong Society of Accountants and a member of the Municipal Services Appeals Board of Hong Kong. In 2006, he co-founded the high-profile pro-Beijing political thinktank in Hong Kong, the Bauhinia Foundation Research Centre. On 10 December 2006, Wu was appointed to the small-circle Hong Kong Election Committee in the CPPCC sub-sector by dint of his membership of that organ. He had been a member of the National Committee of the CPPCC since as early as 2004. In 2010, Wu was elected chairman of the Hong Kong General Chamber of Commerce, having been Vice-Chairman for at least six years, and served a two-year term of office.
In 2014, Wu was found guilty of professional misconduct by the Hong Kong Institute of Certified Public Accountants for acting concurrently both as financial advisor to and auditor of New China Hong Kong Group prior to its collapse in 1999. He was struck off for two years and fined HK$250,000 plus the Institute's costs. The Institute, exceptionally, issued a statement in July 2014 in response to unrepentant remarks by Wu, in which it stated that his breaches had been "persistent, flagrant and inexcusable".