If I buy and sell the same stock or ETF many times throughout the year (basically day and swing trading), to the point where by the end of the year the total "acquisition cost" or "cost basis" put into it reaches (as an extreme example) $500,000,
Will that matter when it comes time to do taxes? Or, will all that matter be the amount I actually profited (or lost) ?
For example, let's say my portfolio is only worth $20,000, but after purchasing, selling, and repurchasing the same stock over and over again, I ended up with an "acquisition cost" of $500,000-worth of the same stock throughout the year, and by the end of the year I had "liquidated" $510,000 worth of the stock (for a $10,000 gain),
Will I only need to pay taxes on the $10,000? Or do the huge amounts of $500,000 or $510,000 somehow come into play?