strengthened. While market volatility remained generally low, isolated bouts of volatility resulted in a more uneven equity performance. In the UK, growth softened further amid heightened uncertainty around Brexit developments, reflected in a volatile and depreciating sterling. Barclays has been working on plans with respect to the UK’s departure from the EU in 2019. Our plans are driven by an overriding commitment to preserve seamless ongoing EU market access for Barclays and our customers and clients. A key element of our plans was to seek regulatory authorisations from the Central Bank of Ireland and the European Central Bank to expand the operations of Barclays Bank Ireland PLC (BBIPLC). Barclays has had a banking licence in Ireland for almost 40 years. During 2018, Barclays received the necessary authorisations, scaled up our presence in Ireland, and began the transfer of our European branches from BBPLC to BBIPLC. We remain confident in our ability to serve our customers and clients once the UK’s withdrawal is complete.Our US Intermediate Holding Company (IHC) received positive feedback from the US Federal Reserve on the IHC’s first-ever public stress test submissions, indicating the strength of the IHC’s capital position. The IHC, which we established in 2016, is an umbrella holding company for our US subsidiaries, including the US broker-dealer that operates key investment banking businesses and the entity that operates Cards & Payments in the US.Risks to the operating modelGeopolitical and macroeconomic uncertainty in some markets remain a risk, while the volume and reach of regulatory change continues to require significant attention. The potential impact of longer-term uncertainty is a sustained low rate environment, predominately impacting revenues and driving cautious market activity. This was evident in 2018, and created a challenging operating environment for corporate and investment banking activities in particular. As we accelerated our growth efforts in 2018, we increased our focus on ensuring that new revenue opportunities do not compromise our prudent approach to risk, or our ability to generate sustainable returns. Coupled with our cost efficiency programmes, this balanced approach is designed to deliver a more attractive bottom line. We have a conservative risk profile, and continue to work to maintain the quality of our lending book. The quality of our US credit card portfolios has been consistent with the overall industry and key competitors. After an increase in delinquency rates in 2017, rates moderated for both the industry and Barclays in 2018. Loss and arrears rates are still below the long-term average and below pre-recession levels, driven in part by favourable US GDP growth and low unemployment rates. We continue to monitor overall growth in unsecured debt across the industry, particularly relative to wage growth, and during 2018 unsecured debt growth slowed to 4.9%, compared with 6.7% in 2017.