You can't claim more than $3K in capital gains losses for a single year, and it's too late to sell for this year and claim. You'd have to claim it when you file 2016 taxes in 2017. And still, you can only claim $3K/year in losses, so if you sell for a $20K loss, it'd take over 6 years to get all of it deducted.

With Baltia this close to getting a pass, selling seems to be a completely impulsive move, not one based on the facts.