Par value is one of those legal mysteries involved in forming a business that entrepreneurs have never heard of and ten minutes after incorporation, may never consider again. However, I ran into a situation recently where it mattered to one startup company (at least for a moment). For a quick bit of history, par value is an anachronistic concept where the company sets a stated value on each share of stock it authorizes. States allow that par value to be any any amount, but typically it is set at zero or some very small value. In the past, this amount had legal effect and represented that amount that was originally paid for the stock and made up the initial capital of the company. However, now, it has little import aside from some minor accounting issues and calculating state taxes in some states (like Delaware).
I am working with a startup that was incorporated in Massachusetts and is now considering a reincorporation in Delaware. The founders originally choose to have "no par value" as is permitted in Massachusetts and did not give another thought to it because of what I stated above and because annual fees for corporations in Massachusetts are not based on par value.
When reincorporating in Delaware, the founders increased the number of shares (to provide some flexibility with investors and with employee equity plans) and assumed that the company would use the same no par value stock. But in Delaware, there are two methods for calculating the franchise taxes that the company must pay every year. Without going into the particulars of each of the calculations (because you would fall asleep on your keyboard), the franchise tax with stock at a par value of $0.01 per share resulted in an annual franchise tax of $350.00 whereas the same amount of stock with no par value could result in a franchise tax of $75,075!
The bottom line. In thinking of par value, do not think any more than this: just go with par value of $0.01 or less and don't think about it again.