Underlying profits for the year were in line with the society's expectations.
Principality saw new net retail mortgage lending of £499m in 2019 helping to take total assets to over £10bn for the first time in the society's history.
The Society attracted an additional £596m of new savings.
Underlying profits for the year were £39.8m and in line with expectations.
Mike Jones (pictured), interim chief executive at Principality Building Society, said: “I am very proud of our performance and the excellent service we continue to deliver to our members.
"Our aims are very much focussed on securing the long-term future of the society and our underlying reported profits reflect the cost of the significant investment we are making in modernising the technology which supports our mortgage and savings businesses.
"This will make our mortgage application process simpler and more efficient for our customers and mortgage brokers to use.
“Our strong capital base, supported by our low risk business model, allows us to take a long term view when investing in the business.
"Being a safe and secure home for our members’ savings is crucial to the ongoing success of our business.
“This is an exciting period in Principality’s history.
"Our goal is to secure the future of the business for our next generation of members.
"While we are investing in technology, our commitment to the high street is undiminished.
"As bank branches on the high street in Wales continue to close, our presence is strong with 70 branches and agencies across Wales and the borders.
"Our business continues to invest in branches while others are shutting theirs.
"As a major business in Wales, we want our towns to be thriving and financial service organisations have a role to play in ensuring towns and communities prosper.”
Principality's commercial team also made £50m available in competitively priced loans to help smaller housing developers build homes across Wales, together with £75m of funding for housing associations to support the creation of affordable homes.
In 2019, Principality provided financial education to more than 11,000 children.
The society invested £110,000 and helped thousands of school children to earn the equivalent of a GCSE.
"Colleagues also raised £156,000 to be shared equally between our charity partners Teenage Cancer Trust Cymru and Alzheimer’s Society Cymru.
Jones added: “I expect the economic environment in 2020 to remain challenging and competitive.
"Nevertheless, our strong capital base means the business is able provide a safe and secure home for our members’ savings irrespective of the prevailing economic climate.
“The society is built on strong foundations and we have consistently demonstrated our ability to thrive in challenging market conditions.
"Continuing to grow and invest in our business and in our colleagues, will ensure that we provide the outstanding service our existing members have come to expect.”
