The North East city was followed by Liverpool and Blackpool, with average yields of 5.22% and 4.58% respectively.
Meanwhile, yields are also strong in parts of London. For example, East Ham has average yields of 4.81% – the highest in the capital – followed by Stratford and Poplar, near Canary Wharf, where average yields have now reached 4%.
Catherine Shinerock, head of marketing and customer support for Advanced Rent Option (ARO), said: “Despite the lockdowns, BTL investors are still experiencing healthy yields, with Sunderland and Liverpool offering some of the best yields in the UK and excellent occupancy rates.
“Liverpool is experiencing a booming BTL market, with demand for high-end, quality rental accommodation outstripping supply. The city has one of the largest universities in the UK and an increasing student population, combined with rising graduate job opportunities.”