If you bought AND sold a stock for a gain within a year that would be taxed as a short term capital gain (which, obviously, would be taxed more than a long-term capital gain).
However it's my understanding that if you bought and sold stocks, bonds, etc numerous times within a year (of which those transactions netted a gain for the year) then your gains would be taxed as ordinary income---and that you would have to file a 1099 quarterly (and classify yourself as a "day trader").
That's based on what I read from the IRS website.
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