Hard to borrow

Hi, I’ll like to check, whats the trading logic for signal followers when the trader shorts a hard to borrow stock?

For example, there are only partial fills on IB because of the lack of inventory, and the other subscribers on MB with no shares to short at all.

AutoTrade sends the short sale request to broker accounts, and brokers fill it if they can, ignore it if they can’t.

In terms of the C2 Model Account, we always assume a stock is shortable, which is unrealistic of course, and one of the many reasons why hypothetical results offer differ from real-world trading.