Campaigners from the charity Christian Aid are preparing to ask FTSE100 companies for greater financial transparency as part of their campaign against tax evasion by multinationals operating in poor countries.
The volunteers and staff have bought or borrowed shares in multinationals to gain access to shareholder meetings, and plan to challenge Shell and HSBC at meetings this week.
Katharine Teague, Christian Aid's Senior Adviser on the Private Sector said: "It's no longer acceptable for big companies to avoid tax aggressively."
She said poor countries lose an estimated US$160 billion (£100 billion) a year to tax dodging by multinationals.
The campaigners have already posed questions to Glencore, Rio Tinto, Barclays, Schroders and BP, and plan to target the meetings of Shell, Royal Bank of Scotland, Diageo, Tesco and WPP shortly.