Confused about "Margin Credit Balance" in Fidelity account

[ctuser1]

I am in the process of moving our yearly $30k to 529 account. To this end, I sold a $16,303.14 position in FXAIX in a fidelity taxable account day before yesterday.

Today I see this $16276.14 automatically put in the core money market fund SPAXX. This is great!!
The remaining/missing $27 is showing up as "Pending Activity" - which is confusing.

So I went into more details, and apparently this is "Margin Credit Balance".

The actual transactions look like as follows:
YOU SOLD FIDELITY 500 INDEX FUND (FXAIX) (Margin): $16,303.14   
JOURNALED JNL VS A/C TYPES (Margin)                       : -$16,276.14    
JOURNALED JNL VS A/C TYPES (Cash)                          : $16,276.14   

Can you please explain what is going on here?

My primary concern is if I am paying any hidden cost I don't realize when I have a margin account, even when I am not actually trading on margin.

[Rob_bob]

By any chance were any dividends reinvested like the day before you sold?  Sometimes a very recent purchase can cause a settlement issue.

I'm with TDA and sometimes when I make a purchase with cash in the account and it shows as a margin purchase for a day or two, but not always.  Or just moving cash from my account to my bank will show as margin.  However it never shows any margin interest paid on the statement.  OTOH I sometimes see an expense amount for "Other" on my statement and have no idea what it is.

[secondcor521]

https://lmgtfy.com/?q=fidelity+customer+service+phone+number

[celerystalks]

Sometimes at Fidelity, retirement and other special tax accounts have a limited margin account.  Im not entirely sure why they call it that, but it is used to allow to allow the account owner to trade on unsettled cash. Basically so that sell-to-buy transaction can be completed in the same day with exchange traded products. Otherwise an investor might be required to have the trade settle before the tax advantaged would be allowed to trade on the proceeds.

Tldr:I think fidelity believes that trading on unsettle cash constitutes a loan from them to you based upon the anticipated settled proceeds of a securities sale, so they journal trades against it as a margin trade for the few days it takes to settle.

[ctuser1]

Sometimes at Fidelity, retirement and other special tax accounts have a limited margin account.  Im not entirely sure why they call it that, but it is used to allow to allow the account owner to trade on unsettled cash. Basically so that sell-to-buy transaction can be completed in the same day with exchange traded products. Otherwise an investor might be required to have the trade settle before the tax advantaged would be allowed to trade on the proceeds.

Tldr:I think fidelity believes that trading on unsettle cash constitutes a loan from them to you based upon the anticipated settled proceeds of a securities sale, so they journal trades against it as a margin trade for the few days it takes to settle.

Thank you. This makes sense.