cash out ibond会产生tax effect, 卖出的当年treasurydirect网站应该会生成一个1099表，要自己下载，如果是孩子的ssn买的，这个税表会是孩子的名字，你要给孩子报税。

看看form 8814 If your child's only income is interest and dividend income (including capital gain distributions) and totals less than $12,500, you may be able to elect to include that income on your return rather than file a return for your child. See Form 8814, Parents' Election To Report Child's Interest and Dividends