Mae Deddf Cymru 2014 yn sefydlu ystod o bwerau cyllidol i Gymru. Mae’r pwerau hyn yn cynnwys datganoli treth dir y dreth stamp a'r dreth dirlenwi, benthyca i gefnogi buddsoddi cyfalaf ac i reoli amrywiadau cyllidebol yn sgil datganoli trethi, a'r gallu i ddeddfu ar gyfer gweithdrefnau cyllidebol y Cynulliad.
The Wales Act 2014 establishes a range of financial powers for Wales, including the devolution of stamp duty land tax and landfill tax; borrowing to support capital investment and to manage budgetary fluctuations arising from tax devolution and the ability to legislate for the Assembly's budgetary procedures.