Cost basis for reinvested dividends

If you reinvest dividends on a stock and the broker charges a fee for reinvestment, is the fee part of the cost basis for the stock?  For example, if the dividend is $100 and the fee is $1, $99 is used to buy shares in the reinvestment plan.  Would $100 be added to the cost basis for the stock or would it be $99?  

 

Thanks for any help!