The magnetic properties of magnetite (Fe 3 O 4 ) are strongly dependent on the internal stress related to stress-controlled regions and to closure domains associated with defects. The contribution of internal stress to the low-temperature magnetic properties of magnetite was tested using annealed and unannealed multi-domain (MD) magnetites. During low-temperature cooling, a room temperature-induced saturation isothermal remanent magnetization (SIRM) increased abruptly at the Verwey transition (T v ∼122K). In particular, the absolute intensity jump (δ VJ , defined as the jump in SIRM at T v upon cooling) resulted from the high-coercivity fraction of MD grains. We observe that annealing significantly reduces internal stress and thus decreases the average microcoercivity. Comparison of the alternating field (AF) demagnetization spectra of δ VJ both for annealed and unannealed magnetites directly links δ VJ to the internal stress. It is likely that removal of the closure domain associated with stress-controlled regions was dominant when the peak AF was less than the average micromagnetic coercivity 〈h c 〉, resulting in a net increase of δ VJ with increasing AF. However, when the AF exceeded the 〈h c 〉 threshold, δ VJ decreased because the stress-controlled regions were demagnetized. Such observations could therefore be useful for estimating the 〈h c 〉 of MD magnetite.