Ffordd arloesol o fuddsoddi mewn seilwaith cyhoeddus yw'r Model Buddsoddi Cydfuddiannol (MBC).   Cafodd MBC ei ddatblygu gan Lywodraeth Cymru i ariannu prosiectau cyfalaf mawr oherwydd prinder arian cyfalaf.  Mae’n cadw elfennau gorau model yr Alban nad yw’n dosbarthu elw, ond yn sicrhau hefyd fod y buddsoddiad yn cael ei briodoli i’r sector preifat a’i fod felly yn ychwanegol at fuddsoddi sy’n cael ei ariannu o gyllidebau cyfalaf.
The Mutual Investment Model (MIM) is an innovative way to invest in public infrastructure.  The MIM has been developed by the Welsh Government to finance major capital projects due to a scarcity of capital funding.  It retains the best elements of the Scottish non-profit distributing model, while ensuring that investment is classified to the private sector, and is consequently additional to investment funded from capital budgets.