Ellington Residential Mortgage REIT functions as a real estate investment trust (REIT), with its core business focused on the acquisition, investment, and oversight of assets tied to residential mortgages and real estate. The company's holdings primarily include various Residential Mortgage-Backed Securities (RMBS), such as government-backed agency pools and agency Collateralized Mortgage Obligations (CMOs). Additionally, it invests in non-agency RMBS, which encompasses non-agency CMOs ranging from investment-grade to non-investment-grade ratings.