Netonline
Via deze handige tool is het mogelijk om snel een percentage te berekenen
http://www.netonline.be/financieel/procenten_berekenen.asp
Smartstops
Smartstops are sell indicators published for each stock every market day. if your stock falls enough to trigger a smartstop, it is an indication that the stock has an increased risk of further decline and you should consider selling. smartstops and protection services help investors rapidly respond to deteriorating market conditions — enabling them to lock in profits, minimize loss and achieve higher total returns.
http://smartstops.net/