clear separation between energetically important terms (|∆E IJ | > 10 -3 E h ) and those that are very nearly zero. Linear fits to the data in Fig. afford slopes of 1.12, 0.85, and 0.81 for the def2-ma-SVP, def2-ma-TZVP, and def2-ma-QZVP basis sets, respectively, with R 2 ≥ 0.9 in each case. (Results are similar for the other systems and best-fit parameters can be found in Table .) A slope greater than unity implies that ∆E IJ is more attractive at the ωB97X-V level as compared to HF-3c. In three of four examples, this happens only for the def2ma-SVP basis set while other slopes are less than unity. In the remaining case (1O48), the slope is closest to unity for def2-ma-SVP and smaller in the more complete basis sets (Table ). All of this behavior is indicative of significant BSSE in the double-ζ calculations. Close agreement between triple-and quadruple-ζ values for the two- body corrections suggests that the BSSE is largely eliminated using def2-ma-TZVP, which is typical for small fragments. Correlations between HF-3c and ωB97X-V are much less pronounced for the three-body terms (Fig. ), with R 2 ≈ 0.4. The lone exception to this trend is that HF-3c and ωB97X-V values of ∆E IJK correlate very well for 1O48, with R 2 = 0.93 for HF-3c versus ωB97X-V/def2ma-QZVP, for example. We regard this as a coincidence as it is not borne out in the other three systems considered. Three-body terms may not be reliably captured using HF-3c due to the minimal basis set, since polarization is the most important three-body contribution, although it is also possible that the three-body interactions are exaggerated by ωB97X-V calculations in a doubleζ basis set. Setting aside the ωB97X-V/def2-ma-SVP results in Fig. , which are significantly impacted by BSSE, it does appear that HF-3c can at least identify the small number of three-body terms whose magnitude is significant.