AITA for refusing to split the inheritance after finding out my mom had a secret savings account?

When my mom died last year, I thought everything would be straightforward. She wasn’t rich or anything, just a retired nurse with a small house and a decent pension. But she always made it clear that whatever she had would be split between me and my sister 50/50.

So when her lawyer called us in, I didn’t expect any surprises. Just grief, logistics, and a bunch of sad paperwork.

Instead, we found out she had a secret savings account with over $180,000 in it. Not mentioned in the will. Just sitting there in an account under her name, discovered after the bank contacted the estate.

I didn’t even know she had that kind of money. My sister definitely didn’t.

Things Got Weird Fast

Here’s where it gets complicated: the account listed me as the joint holder. Not a beneficiary. Joint. Meaning the money legally passed to me the second she died.

No probate, no questions. Just mine.

My sister lost it.

She said our mom would never have wanted that. That she must have meant to add her too, or just hadn’t gotten around to including it in the will. That it was morally wrong for me to keep it. She kept throwing the word fairness around.

I asked the lawyer. He was pretty blunt: legally, it’s mine. Morally? He said that was between me and my conscience.

The thing is… I always helped Mom with her finances. I was the one who took her to doctor’s appointments. I helped her move when her knees gave out. I managed her bills for the last few years. My sister lives three states away and visited maybe once a year.

So yeah, maybe Mom did it on purpose. Or maybe not. But part of me feels like if she trusted me enough to put my name on that account, she knew what she was doing.

I did offer my sister $20k. Not because I think I owe it to her, but just to keep the peace. She called it “insulting.”

She said I was being greedy and disrespecting our mother’s wishes. That if I keep the money, she doesn’t want to speak to me again. And she meant it.

Now I’m sitting here with this money and this silence between us. I keep second-guessing everything.

What if Mom did mean to include her? What if she just forgot? What if she was planning to tell us and never got the chance?

But then I remember this one thing she said to me, a few months before she passed. We were at the bank, and she kind of half-joked, “At least one of you won’t have to wait for the court vultures to circle.”

I didn’t think much of it at the time. But now…

It just feels intentional.

And honestly? My sister’s sudden righteousness would sting less if she hadn’t bailed on Mom when things got hard.

So… AITA?