Short Call Option Strategy

Selling a call without owning the underlying shares is what this template prices. The premium is collected up front and kept if the option expires worthless, but assignment obliges delivery of stock at the strike no matter how high the price has gone, so the loss on a naked call has no upper bound.

Bid, ask and previous close arrive on demand from the option symbol built out of your inputs, beside the stock's last price, so the credit and the breakeven at strike plus premium stay current. Margin requirements for writing calls without the stock are set by your broker.