In late August, UK challenger bank Tandem confirmed a long-awaited fundraising and announced what it hopes will be a game-changing acquisition. But the identity of one of its financial backers for the deal raises some interesting questions.

Tandem said in its 24 August statement that the acquisition of Allium Lending Group, a green-energy lending business, came “as part of” its £60m fundraising. Neither the investors in the round nor the valuations of Tandem or Allium were disclosed.