Litigants (and federal district courts) that address awards of prejudgment interest must determine whether state or federal law applies to calculate the amount of interest. For example, in a case brought in a federal district court in New York State, when the claims concern purely federal law, should interest be calculated based on a federal statute or on the 9% interest rate set forth in the New York State Civil Procedure Law and Rules Section 5004? The guidelines here, despite some outlier decisions, are straight-forward. Click on the Following Link to Read Full Article. Prejudgment Interest in the Federal Courts—Does Federal or State Law Apply?