Question about negative buying power

So I owned 30 shares of Nvidia this morning and saw the price drop from 250$ a share to 248$ and decided to sell them since i had a feeling the price would keep dropping all day because of the upcoming rates announcement on Wednesday. I predicted that the bottom for the day would be around 240$, which was the price that i initially bought in about 1 month ago. Sure enough, around lunch time the price per share was 240$ so I bought back in, actually using my profits to buy an extra share. So I am happy with the move, I now own 31 shares at 240$ each and I avoided being down hundreds but i couldn't help but notice that my buying power is now -93 dollars. My brokerage account is in CAD so I'm thinking it may be conversion rates? Ive been researching for an hour now and my bank customer service is closed, I can't put my finger on why I have negative buying power. I have 10,000 CAD in the account, -93 buying power should be nothing then? Any explanation would be appreciated please

Submitted March 19, 2018 at 08:59PM by macNy http://ift.tt/2HNGXn0