Recently, we have applied the domain-based local pair natural orbital approach to full coupled-cluster triples, being, to the best of our knowledge, the first local natural orbital based linear-scaling CCSDT algorithm to be implemented. The development of DLPNO-CCSDT opens the door for the extension of local pair natural orbital based coupled-cluster theory to quadruples. The incorporation of quadruples converge coupled-cluster relative energies to within 1 kJ mol -1 when compared to FCI. Due to the high O(n 10 ) cost of CCSDTQ, many approximations for quadruples have been devised. The most successful is the (Q) correction, accounting for, on average, around 90% of the difference between CCSDTQ and CCSDT, and agrees with full CCSDTQ exceedingly well in regards to relative energies. Because of this, CCSDT(Q) has been coined the "platinum standard" 23 method of quantum chemistry. Analogous to the relation between (T) and full triples, (Q) reduces the cost of quadruples down an order of magnitude to O(n 9 ). Due to the mathematical complexity of implementing higher levels of coupled-cluster theory, as well as the more stringent accuracy requirements, there has been prior work done on a local quadruples algorithm compared to triples. Non-local natural orbital approaches to quadruples have previously been implemented, such as the work of Rolik and Kallay 43 , who used MP2-based frozen natural orbitals (MP2 FNOs) to implement CCSDT(Q). Although this leads to some impressive speedups, it does not fundamentally change the scaling. In addition, very tight FNO tolerances are often needed for sufficient accuracy since the natural orbitals are computed at the MP2 level, and not updated to be recomputed at a higher level of theory.