This technical note investigates the interconnectedness between the market-based finance (MBF) sector in Ireland and the rest of the financial system, with a view to assessing potential financial stability risks. Ireland has made good progress in implementing the recommendations from the 2016 Financial Sector Assessment Program, but some important data gaps remain to be closed. While many linkages between the domestic economy and the MBF sector have been analyzed, challenging data gaps and opaque linkages relating to the other financial institutions (OFI) residual should continue to be explored through ongoing cooperation at a domestic and international level. The Central Bank of Ireland’s fund stress-testing model remains under development and there remain some gaps in terms of granular data collection and analysis of the interconnectedness and composition of the significant activity of the remaining OFI residual. The analysis suggests that, notwithstanding progress, work remains to be done to elucidate fully the linkages between parts of the MBF sector and the rest of the financial system, and to the domestic economy, to explore further areas of potential systemic risk.