@zucc57 said " I read that there are several ways of calculating gains when an asset such as this is sold"
Not really. In your case, not at all, since you will be selling all shares and there was only one purchase in the past.
People wo make multiple purchases, including dividend reinvestment, and/or multiple sales are allowed to choose among various cost basis methods. But they must choose in advance of making sales and must stick with the original choice for all sales.
