Principality has opted to retain £100m of the issuance, thus providing net external funding of £375m.
The RMBS, called Friary No 3, is triple A rated by both Fitch and Moody’s credit rating agencies.
Steve Hughes, Group Finance Director at Principality Building Society, said:
“This is the Society’s third RMBS – the first, Friary No 1, was successfully completed in 2011 and Friary No 2 was completed in 2014. As a mutual building society, we rely on retail savings to fund the majority of our lending and we remain committed to this model.
“However, it is also important that the Society builds a stable, diversified funding base for the long term. The RMBS diversifies the Society’s funding base and underpins our growth strategy. This not only strengthens our overall balance sheet, ensuring that we provide the essential level of capital to provide safety for our savers, it also enables us to further improve our ability to lend and build our share of the increasingly competitive mortgage market.”