Once I was on an automated monorail at a zoo and my wife and I were the only people on the train at that moment. I wondered, what would happen if I forced the d

Once I was on an automated monorail at a zoo and my wife and I were the only people on the train at that moment. I wondered, what would happen if I forced the doors open? The answer is that the train stopped immediately and eventually someone came on the intercom, asked us not to bump the door, and then the train restarted. Another time, I was using a public restroom and it contained a very large red button with a very large sign that read "ATTENTION DO NOT PUSH RED BUTTON UNLESS IT IS AN EMERGENCY"[1]. I did not push the button and my curiosity about remains unsatisfied. Point is, just because the Federal government ordains that the limit on series I bonds is $10K purchased electronically plus $5K purchased with tax refund per tax ID[2] per calendar year, you shouldn't expect the web site itself to enforce this limit. There's all sorts of ways you can accidentally or intentionally exceed limits, sometimes systems will catch them, but sometimes not. In prior years, you could even apparently get away with exceeding the limit with no more than a stern warning not to do it again[3]. I'm fairly confident OP misinterpreted the emails they got from Treasury Direct, and that the Treasury will refund the excess amount of the purchase, not full transaction amount. At this point, they own $10K in Series I bonds and will receive a refund for the excess $10K. I'm curious if they'll get the refund as a single transaction for $10K, or as two transactions of $25 and $9975. [1]: https://imgur.com/jAKRPQt https://imgur.com/jAKRPQt [2]: You can use "Entity Accounts" to purchase additional bonds. https://www.treasurydirect.gov/indiv/help/tdhelp/help_ug_292-entityaccountslearnmore.htm https://www.treasurydirect.gov/indiv/help/tdhelp/help_ug_292... [3]: https://old.reddit.com/r/personalfinance/comments/na13f/exceeding_the_i_bond_limit_on_treasurydirect/ https://old.reddit.com/r/personalfinance/comments/na13f/exce...