["International Economic Review, Volume 67, Issue 2, Page 657-696, May 2026. ", "\nABSTRACT\nHow do rental investors affect housing price dynamics? I develop a search model that allows housing owners to invest in rental housing. The model matches the high investor share and housing price increase observed in a housing boom in Oslo, Norway, while featuring increasing price‐to‐rent, and correlation of the buy‐to‐let share with housing price growth. In the model, an exogenous shock to population inflow increases demand for both owned and rented housing. Increased rental demand induces more buy‐to‐let investors to enter the market, adding extra demand to the housing market. Search frictions are important to explain an increasing price‐to‐rent ratio."]