Devander:
I think you can only use this ploy if you bought your shares at two or more prices. So if you bought 500 shares of BHP at $26 and another 500 at $ 32, and then sold 500 at $ 33, you could deem that the 500 you sold were at a cost basis of $ 32 so only a profit of $1 and not $7 per share.
So you either choose first in first out or average cost
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