If you're shipping or using the service of a courier company, the chance is that you've come across a figure that is stated as declared value. For example, if you are shipping with a bay area courier, every package you send with them, whether staying within the area or going further abroad, is going to have a declared value. This is the maximum that the company is going to be liable for if something happens to your package. This number is not solely reflective of the actual value of your goods, as all companies are going to have maximum amounts that they are able to list as a declared value. This number may be different for the different kinds of divisions the courier service you deal with has. For example, the maximum declared value for a package transported by bike messenger is going to be quite different than the maximum declared value for a load of cargo going cross country.
If you are shipping something with that bay area delivery company and it is worth more in value than the maximum declared value for that kind of shipment with that particular company, you may want to look into some alternate insurance options. That maximum declared value is the most that the company is able to be held liable for in the event that something happens to your package. This can, and does, cover all kinds of damage, such as vehicle accidents, theft, and weather. However, if something happens to your package and it is worth more than the declared value, even if they are at fault, that delivery company is only liable to that amount.
If you need more insurance, talk first to your company that you are shipping with. Some have agreements with insurance companies where, for a fee, you can add a rider on to cover your shipment up to your chosen value. In other instances, the company may not have any such package or arrangement. In these situations, it will be up to you to try and find an insurance policy through your existing insurance company or a new carrier that can cover your shipment in the event of anything untoward taking place while it is being shipped. The amounts of insurance that you can purchase are, in theory, endless, and you simply need to find an insurance company that will cover you at the prices you want up to the actual value of the shipment that you feel you need protected.