Disclosed are improvements to a method for account reconciliation comprising improved, extended, and more flexible algorithms for (1) automatically determining what transaction features are best candidates for matching diverse datasets; (2) automatically determining how logically to subdivide accounting datasets prior to reconciliation; (3) matching groups of transactions (allowing one-to-many, many-to-one, and many-to-many matches instead of just one-to-one matches); (4) making use of more types of transaction feature, including transaction dates (where proximity of two transactions in date may be significant even if the dates do not exactly match). The improved method is, therefore, better able to perform its intended function of identifying matching transactions. It is applicable to a wider class of problems while still saving significant costs and labor, and still retaining flexibility in not requiring source data in a particular format, and not being domain-dependent or requiring extensive user setup.