In the UK it would depend on the type of crowdfunding transaction.A crowdfunding scheme launched by a charity for its charitable purposes where the funds were a donation would qualify as charitable donation and would therefore be tax deductible.Some crowdfunding equity transactions for business qualify as Enterprise Investment Schemes (30% tax relief on investments up to u00a31m) or Seed Enterprise investment Schemes (50% tax relief on investments up to u00a3100,000). These investments qualify for generous tax relief in fact the tax relief might be at higher than your marginal rate.There are specific rules that must be met to be a qualifying scheme.