John Kingman is the second permanent secretary at HM Treasury, having previously been the managing director at NM Rothschild & Sons Ltd and the CEO of UK Financial Investments (UKFI), the body set up in late 2008 to manage the Government's investments in Britain's banks.
In December 2009 it was approved that Kingman would become the managing director of NM Rothschild & Sons Ltd in March 2010. ACOBA approved the move "subject to the automatic three-month waiting period from his last day of service and the conditions that, for 12 months from the same date, he should not advise UKFI, Royal Bank of Scotland, Lloyds Banking Group, Northern Rock or Bradford & Bingley, or be personally involved in lobbying UK Government Ministers or Crown servants, including Special Advisers, the Financial Services Authority or the Bank of England on behalf of his new employer or their clients".
In September 2012 it was announced Kingman would be leaving NM Rothschild & Sons Ltd and would returning to the public sector as the second permanent secretary at HM Treasury, with responsibility for the economics functions, particularly growth, financial services, and infrastructure.
In October 2016, he again sought advice from ACOBA to take on the role of chairman of Legal & General, the British multinational financial services company that deals in life insurance, general insurance, pensions and investments. The committee noted that Kingman had had dealings with the firm during his time as HM Treasury, and was involved in policy which directly affected them. He had also had limited contact with several of the firm's competitors. The committee found however that his dealings with the firm had been infrequent, and most of the policy determinations that affected Legal & General were carried out by other teams in Kingman's department; additionally, during his time in office he had no access to any competitively sensitive information about Legal and General, and none of Legal & General’s competitors raised any concerns about his prospective appointment. ACOBA also recognised that 'as soon as he was approached about the role with Legal & General, he declared it to his department, and arrangements were put in place to ensure he stood aside from any related issues'. The committee therefore approved Kingman's appointment, so long as he did not take up the post until 22 October 2016, he would not draw on any information available to him from his time in Crown service for the benefit of the organisation, and he would not personally participate in any lobbying activities on behalf of Legal & General. ACOBA had also agreed that it was in the public interest to stay on as acting HMT permanent secretary, 'to prevent there being a gap at a critical time'. 
- John Kingman and Glen Moreno to appear before MPs, Telegraph 08 Feb 2009
- Simon Watkins Fury as credit crunch civil servant lands Rothschild job The Daily Mail, 22 November 2009, accessed 27 November 2014
- Eleventh Report 2009-2010 Advisory Committee on Business Appointments, accessed 27 November 2014
- David Thomas Rothschild head returns to HM Treasury Financial News, 12 September 2012, accessed 27 November 2014
- Summary of business appointments applications - Sir John Kingman, GOV.uk, 18 October 2016, accessed 18 October 2016.