<p>The impact of institutional investment on residential rental markets is a topic that draws much attention, but for which limited evidence exists. This paper assesses the direct and indirect impact of institutional investment in existing housing stock on residential rents at the property level, using Ireland as a case study. Ireland’s experience of the Global Financial Crisis (GFC) produced a quasi-natural experiment where large portfolios of rental properties became available for purchase, enticing institutional investors into Ireland’s rental market for the first time. By focusing on investment in existing stock, the analysis isolates the impact of institutional investment from any supply effect associated with it being channelled into new rental housing. The study finds that institutional investors increased the level of rents by 4.1 percentage points more than other landlords with comparable properties following purchase.</p>