Be Careful Trading on Mobile App!!
I recently used the Fidelity mobile app to do some rebalancing in my 401(k) accounts. My Roth was fully invested in Security A, and I wanted to sell all Security A (in that account) and buy an equivalent amount of Security B. I logged into the app, selected the account I wanted to trade with (the Roth) and then the security I wanted to trade. Since I wanted to sell the full account value, I pressed the "sell all" button that appeared and waited. Two seconds later, the trade posted - for an amount 3x the value of that account.
Unbenkownst to me, the Fidelity app had automatically changed the account I was trading in from my untaxable Roth 401(k) account to my *very taxable* Individual account. I hold the same securities in both, so nothing had seemed off. In less than ten seconds I had created tens of thousands in taxable income for the year.
This is an easily replicable issue; you can try it right now on your app. Select any account, hit the trade button, then select any security you hold in more than one account. It will disregard your earlier choice and pick an account at random (as best I can tell) for trading that security, from the list of accounts that hold it. You can see this on the confirmation screen before making the trade, but
Fidelity's response was that "there are no reported bugs" and that responsbility for this is 100% on me. I recreated the issue on screenshare with a rep and she argued that I "should have selected the account I wanted to trade in." I went back to the step where I had selected the account and showed her again. She went silent for a moment and then fell back on some legal line about ultimate responsiblity being on the customer to verify trades. I thanked her for her time and informed her that, while I understood the legality of the situation, I would be transferring my taxable accounts to another brokerage. The rep then went on to place a security hold on my account and explicitly cited this call as a reason. This made me unable to log in until I had spent another hour (literally) on the phone with support. I wrote this entire post while on hold.
Because this is Reddit, I'm fully expecting a comment section full of people who have never encountered this issue not understanding why it's frustrating, telling me I should "just check the confirmation page," or probably that it's my fault for trading stocks as an app. And all of that is true, but it doesn't change the fact that this is hilariously poor design choice for a billion-dollar consumer financial company. I've used my fair share of brokerages, including a few lower-rent versions, and I've never encountered anything like this.
tl;dr - Don't assume that ust because you selected an account, that's still the account you're trading in. Fidelity's app can change the account with no input and no warning. Speaking for myself, I'm uninstalling it.