Abstract: The present invention provides methods of optimizing certain stable liquid formulations of antibodies that immunospecifically bind to antigens of interest. Such formulations are suitable for parenteral administration to a subject, and exhibit increased stability, low to undetectable levels of aggregation, low to undetectable levels of antibody fragmentation/degradation, and very little to no loss of the biological activities of the antibodies, even during long periods of storage. The methods of the invention provide formulations that offer multiple advantages over formulations produced by non-optimized methods, including less stringent or more readily available transportation and storage conditions, less frequent dosing, and/or smaller dosage amounts in the therapeutic, prophylactic and diagnostic uses of such formulations. The invention further provides methods of identifying antibodies exhibiting certain phase behaviors such that the antibodies can be formulated by the methods of the invention.