So if I sell all of my shares at a loss I will only be able to deduct the amount the shares I had at a loss before I purchased more on Dec 13th?
not quite. today is 12/18/2024 so if you sell all the shares you hold today that would include the shares purchased on 12/13. if sold today, and assuming all shares sold were at a loss, any purchase from 12/18 through 1/17/2025 would trigger a wash sale but for only the number on shares purchased (up to the number sold). There would be added complexities if some shares were sold at a gain
for example, some shares were purchased at $9 and some at $8. All were sold for $8.50. If there was a purchase of an equal number of shares 30 days after the sale then there would be a wash sale on those costing $9 but not those costing $8.
another example, the $9 shares were purchased before the $8 shares and you sold some shares for $8.50 (after buying the $8 shares)
you could tell the broker that you are selling the $8 lot. Thus you have a gain and no wash sale. this assumes the number of shares sold was the same or less than the number of the $8 shares bought.
