Any way to reduce cost basis?

[murray t turtle]

Is not the cost basis the current price?

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Yes, on ETFs for example;
if you entered @ the current price.
On QQQ, i have charts when it was $30 area/so i really wanted to increase my cost basis from $313 area+ did. Pay no tax on a ROTH /back door Roth.
I wanted to increase my cost basis on some more tech ETFs so i sold about 50%of qqq today[Since i increased my cost basis, in qqq from $313;
by selling 50%, increased again my cost basis to $315 area..................................................................]