Today, the prosecution grilled Wang on a single, damning column in FTX’s databases. Called “allow_negative,” it allowed Alameda to have a negative balance. Alameda could withdraw money even when its accounts didn’t have any, and it had an enormous line of credit

From https://www.theverge.com/2023/10/6/23906899/ftx-alameda-sam-bankman-fried-trial-gary-wang-testimony