imation. These benchmarks were obtained at the DLPNO-CCSD(T 0 )/CBS level, where "(T 0 )" denotes a semicanonical triples correction. Benchmarks were reported at the same level of theory for a ligand-protein complex consisting of indinavir bound to a model of HIV-II protease, and for intercalation complex of the anti-tumor agent ellipticine bound to double-stranded DNA, for which a FN-DMC benchmark is also available. The ellipticine@DNA and indinavir@HIV systems, which are also depicted in Fig. , have become standard noncovalent benchmark systems of pharmacological interest. The eight complexes in Fig. are larger than the ones in Fig. and range in size from 86 atoms (for the "tweezers" complex 2b) up to 323 atoms for indinavir@HIV. Due to their size, DFT calculations for these systems employ the def-TZVPD basis set, which should still lie close to the CBS limit once CP correction is applied. Interaction energies for these complexes are plotted in Fig. . Once again, FN-DMC interaction energies are systematically less attractive than DLPNO-CCSD(T 0 )/CBS values, with differences that lie outside of the mutual uncertainties in the putative benchmarks. Errors in the DLPNO approximation have been shown to be vanishingly small when tight thresholds are combined with extrapolation to the canonical limit, even in sizable vdW complexes, and the origin of the discrepancies with respect to FN-DMC remains unresolved.