As a startup founder, shutting down your business will be one of the hardest decisions you'll ever have to make. However sometimes it's also the smartest option. Especially if you're able to close things down gracefully, give folks a good severance package and potentially return some unused funds to investors; not to mention gaining back some valuable time. Unfortunately, many entrepreneurs refuse to admit defeat and keep pouring resources into a failing endeavour. The tendency for people to double down in the face of growing negative evidence is known in behavioural psychology as "escalating commitment to a losing strategy". In this short article I highlight a few of the common cognitive biases that help make this happen.