Protective Call

Caps the risk on a short stock position by buying a call above it, so a rally stops costing money at the call strike instead of running open ended. The call is priced from bid and ask, the shares are marked with last price and previous close, and profit and loss is mapped across expiration prices, showing where the premium paid pushes the breakeven and where the call takes over. Strike and expiry are inputs, making the trade off between the cost of protection and how far the stock can run before it bites easy to test.