Four South American countries have filed amicus briefs to accompany Sullivan & Cromwell’s appeal for the reversal of a staggering $16.1 billion ruling against Argentina, its client in a pair of long-running breach of contract lawsuits.

U.S. District Judge Loretta Preska of the Southern District of New York ordered Argentina, already grappling with severe economic struggles, to pay that huge sum in September, delivering a handsome reward for litigation funder Burford Capital Limited, which helped finance the case.