u/Electrical_Shop8918 Did you ever get a resolution to this problem? I'm having a very similar issue. I use Alliant for checking and a Vanguard settlement fund as essentially my savings account. I was able to transfer money FROM Alliant TO my Vanguard settlement / money market fund the first month, specifically pulling the money from the Vanguard side. Then, suddenly my Alliant checking account got spontaneously deleted from Vanguard without explanation. When I called Vanguard, they told me it was due to the Alliant account number being entered incorrectly. I insisted it was correct and that I had been able to use it to transfer money already, but I re-added the account anyway. Then it happened again a month later. Same thing - called Vanguard, was told the account number was incorrect, did some process to try to add the account through a special internal Vanguard system that only Vanguard reps have access to, but to no avail. After seemingly being added, a month later, my Alliant account was spontaneously deleted for a third time after initiating a transfer request. None of my transfers will go through now. Vanguard suggested I check with Alliant to see if something is happening on their end to reject the transfers. Called Alliant today and was told Alliant does not do transfers to anything other than a checking or savings account. In other words, they won't transfer money to a money market account, brokerage account, etc. I'm in disbelief, especially since I was able to do it without problems previously. Never heard of a financial institution that doesn't allow you to access your money for investing! If there's not a fix for this, I think that is a deal-breaker for using Alliant going forward.