'AITA for refusing to co-sign my sister’s mortgage after my parents went behind my back?' UPDATED
"AITA for refusing to co-sign my sister’s mortgage after my parents went behind my back?"
I (28F) have been busting my butt for years to save for my own house. I work in software, so I make decent money, but it still takes forever to build up a good down payment. Meanwhile, my younger sister (25F) is in grad school with barely any credit.
Our parents (both mid-50s) found a house near them and decided she needs it. They made an offer—without telling me—and now the deal only goes through if I co-sign.
The problem? I had no clue they’d do this. My parents basically dropped a bomb: “You have the best credit score—co-sign so your sister can get the house!” They also hinted I should chip in for the down payment because “you’ve got the money.”
If I co-sign, I’ll be on the hook if my sister can’t pay. She’s still in school, has debt, and zero backup plan. The bank might also reject my future mortgage application since they’ll see I’m already tied to another loan.
But my parents say I’m “selfish” and “forgetting family values.” My sister’s calling me a monster for leaving her “stranded,” and my mom threatened to cut off any future financial help (like wedding money) if I don’t help right now.
Some relatives think it’s insane my parents tried to rope me into this after they already made the offer. Others say I should just do it for “the family’s sake.” I feel guilty, but also mad they put me in this spot. AITA for protecting my own finances, or are they wrong for strong-arming me into co-signing a mortgage I never wanted in the first place?
Later, OP edited the post to include:
I’m actually adopted lmao forgot to mention in my confused and angry state. My parents adopted me when I was very young because they’d been struggling to conceive. A few years later, they had my younger sister naturally, which was a huge deal to them—she was their “miracle baby.”
Ever since, it’s felt like my role in the family became “the older, adopted one,” while she was the golden child who could do no wrong. Growing up, I was expected to pitch in more, be more responsible, and generally look out for my sister.
I worked my butt off in school, snagged scholarships, and eventually landed a good job in software. All the while, I felt like my family mostly saw me as the “fallback option” in case anyone needed financial or emotional support.
Now that I’m actually building my own life—saving for a house, focusing on my career—I’m realizing how my success just makes me look like a bigger piggy bank to my parents.
The more independent I become, the clearer it is that I need to separate myself from the constant guilt trips and the unspoken expectation that I’ll always bail them (or my sister) out. I love them, but I can’t keep sacrificing my own future to maintain a dynamic where I’m never the priority.
Here's what top commenters had to say about this one:
Independent-Stand351 said:
Absolutely do NOT co-sign. NTA if you refuse. Let your Mom not pay for the wedding. If she’s threatening now, she will again. In the end she probably won’t. But that’s not the main reason not to co-sign. The main reason is there is a huge chance you will be in debt for a house that is not yours.
BadAdvice24_7 said:
NTA, that sounds like a terrible idea. Family sounds toxic. Good luck.
she_who_knits said:
Never ever cosign for anything for anyone. I don't care who they are. NTA for following basic common sense. Your parents demands are ridiculously unreasonable.
Cali_Holly said:
NTA. Financial Abuse. This doesn’t sound like the first time OP has been put in this position. You sound financially responsible and goal oriented. Your parents and sister can insult you all they want. But you would be insulting your own intelligence by allowing them to bully you into signing.
Although, you can tell them that you will only co-sign if ONLY your name is on the deed. Sister flakes on the payments? You can sell the house to pay off the loan and will have no problem getting a bank loan to buy the house YOU actually want.
Whoops_my_bad0987 said:
NTA. Your parents and sister are way out of line for trying to guilt-trip you into co-signing something that could literally ruin your financial future. Co-signing isn’t just a favor it’s a massive responsibility. If your sister can’t pay (which sounds super likely), you’ll be the one stuck with the debt, and it could wreck your chances of getting your own house.
The fact that they made an offer without consulting you is wild. They’re basically trying to make their bad decision your problem. Protecting your financial stability isn’t selfish—it’s smart. Family values don’t mean sacrificing yourself for their poor planning. Hold your ground, because you’re 100% right to prioritize your own goals.
Ok_Routine9099 said:
NTA. Run away from this. This will only end in sadness. You will lose your sister and parents when your life needs change and you can’t afford to be on the mortgage. You will lose your family when your sister needs her next handout.
You will lose your family when your sister defaults. If you’re going to cause family disruption by saying no to their toxic request, it may as well be while your credit score is high. There’s a reason theirs is low…
The next day OP came back with this update:
Okay, so here’s where I’m at: I’m absolutely not signing my sister’s mortgage (and I’m definitely not pitching in for any down payment). This whole thing was the final push I needed to realize how messed up our family dynamic has been for ages.
I mean, I’ve always known it was bad, but having them basically try to volunteer me—and my finances—without even asking just crossed a line I can’t ignore anymore.
I’m done. I’ve decided to cut ties. I’m already in the process of dropping any financial entanglements we might have—cutting off shared accounts, making sure they can’t use my information for anything, and basically scrubbing them from my finances.
My job lets me work remotely, so I’m planning to move out of state soon. That was always in the back of my mind, but now it feels urgent. I need space, distance, and a real shot at a normal life without the constant guilt trips.
I’m also locking down my credit—freezing it, changing passwords, everything. I’m not taking any chances that someone might try to open a line of credit in my name. I’ve seen enough horror stories and I’m not about to become one.
Thankfully, I’m not alone in all this. My close friends have been incredible. They’re basically my real family at this point—helping me pack, offering me a place to stay if I need it, reminding me that I’m not crazy for wanting to protect my future. They’ve been the biggest source of support, and I’m honestly so grateful to have them in my corner.
So yeah, that’s it. I’m not signing. I’m leaving. I’m done. If my family wants to blow up at me for “abandoning them,” so be it. I’ve gotta look out for myself, my credit, and my sanity. Here’s to hoping things only get better from here.
Everyone who commented their 2 cents are amazing people and I thank you all for your support while I’m dealing with this. Truly thank you. ❤️
Here's what people had to say after the update:
Reach out to that bank about that specific property and let them know who you are and that you will NOT be signing nor have you signed ANYTHING for you sister on ANY property she might be interested in buying.
Absolutely the right move, your parents were wrong for even asking! As someone who did the same cutting ties, it can be hard sometimes, but write yourself a letter of why you cut ties to be able to read if you ever consider reconnecting.
Maybe but the entire premise of the parents adopting her was that they were having trouble conceiving so adopted in order to have a child. If she was adopted at around the age of 6 then the parents kid that they conceived was already ~3 so the entire reason for adopting her doesn't make sense.
In the unlikely case this is real then OP should put herself first and not co-sign. I don't really believe it is real though although I don't really know the adoption process enough to know if what she stated makes sense for why her timeline doesn't sound like it works.
Adoptions frequently take time. Fostered at one with plans of adoption. So that's when she was brought into the family. At 3 her sister was born. At 6 her adoption was finalized.
fancyapanda OP
Yes this is correct. I was a foster child that my parents took in and later adopted. Looking back I think they fostered me for money. Sorry my timeline is messed up I’m terms of ages. It’s was some time ago and very traumatic for me. So my apologies
As an adopted parent who adopted two of my three children from the foster care system, I am so angry for you!!! I love my kids. I couldn’t imagine doing what your parents are doing. You have every right to be upset, to be independent, but mostly to be loved equally by your parents. Do what you have to do. Sending hugs 🥰 to you.