The Commissioner-designate for International Co-operation, Humanitarian Aid and Crisis Response, Rumiana Jeleva, currently Bulgarian Minister for Foreign Affairs, and a former MEP, is under pressure to dispel concerns about her past ownership of a consultancy firm.
MEPs have asked Commission President Josť Manuel Barroso, and the European Parliament's legal service to look into the matter further.
The candidate, Rumiana Jeleva, faced tough questioning from MEPs on 12 January. She denied any wrongdoing. MEPs can veto the whole Commission if they oppose one of its members.
A Bulgarian MEP from the ALDE group, Antonyia Parvanova, disputed Ms Jeleva's declaration that she had ended her involvement with the Bulgarian firm Global Consult in 2007. Ms Parvanova claims she was still managing the company until 2009. Any undeclared financial interest would put Ms Jeleva in breach of EU rules.
'I have declared everything I was obliged to declare', she told MEPs. 'I have nothing to hide'.
MEPs will vote on 26 January on the whole Commission. It cannot take office without the parliament's approval.
In 2004, Barroso was forced to withdraw Italy's nominee for the post of justice commissioner, Rocco Buttiglione, because MEPs disapproved of his opposition to gay rights.
14 January 2010