Hi, I recently filed my taxes and found out I had to make an amendment to them. My parents had a small UGMA for me that was sold off in 2013(im 23 and out of college) the short term gains were $1086. On my new return I added this from the 1099-B form. After everything was finished on turbotax, it says I now owe $365 federal and $33 state. My initial return was $2570 so I clearly understand why I owe money, but how is it that much? This increase in capital gains did not move me up a tax bracket, and from my understanding it should be taxed 15% and I just don’t understand. My income before and after deductions falls in the $8,926 to $36,250 range(15%)

any help answering this would be very much appreciated!

thanks!