My Citibank Online Balance shows 0 after a one step update. Logging into Citibank web site shows correct amount.
Citi is sending that zero balance via their crumbling Direct Connect. Switch to Express Web Connect+ and you'll get the correct balance as well as a slower download.
This is happening on my CitiBANK savings account, which has not had direct connect in a long time. It is Express Web Connect +.
Direct connect stopped on CitiCARDS this week, forcing EWC+, but that is a different issue.
My Costco Visa Anywhere card works just fine with Direct Connect and is getting the correct online balance.
EDIT: "Mostly" for all the time I have had it there are times late at night that it will have the pending transactions in the Online balance. It gets corrected by the morning.