Arts & Business and Business in the Community, which are both in the Prince of Wales' Prince's Charities group, have announced they have entered into merger talks.
The negotiations began this summer, and an announcement is expected by the end of this year.
It is also the intention that Arts & Business Scotland, Arts & Business Northern Ireland and Arts & Business Cymru will become independent charities.
An Arts & Business spokesman told civilsociety.co.uk that as devolved government funding streams were different across the nations it was a natural step as people on the ground would better understand their national governments.
Arts & Business most recent accounts show it has an income of £6.6m, while Business in the Community’s income is £20.6m.
If announced, it will be the second merger for a Prince's Charities organisation this year – in January the Prince's Trust and youth charity Fairbridge amalgamated.
The Prince's Charities is a group of 20 not-for-profit organisations of which The Prince of Wales is patron or president; 18 of the 20 Charities were founded personally by the Prince.