Are money market funds like VUSXX considered a security? Do you still own the security if the firm fails?

Cash is trash, and I’ve long held the belief that bank deposits are not secure.

However, if a broker fails and you own stocks, you don’t even need SIPC insurance, which covers cash at the broker vs. FDIC insurance, which covers cash at the banks. Instead, you still own the shares and can transfer them to another broker in case of a broker failure.

But what about money market funds like VUSXX? Is it considered a security? Can you transfer the VUSXX shares to another broker if Vanguard fails?

The confusing part is that VUSXX is invested in treasuries, which you should still own if Vanguard fails. But Vanguard actively manages the fund, so if they fail, I’m not sure what happens to your VUSXX shares if they can’t actively manage the fund anymore.