I know this should be easy, but I can't make it work. Help!!

I'm trying to build a report for a bank that totals all of their customers'
portfolios, by type of asset. Each security in a portfolio has a
classification code linked to it, & I want total by a group of those codes.

ex:

ASSET MARKET VALUE CLASS CODE
IBM 500,000 400
GE 2500 420
KO 500 499
US BOND 10,000 600
MNY MKT 15,000 850

I'm trying to do a sum of market value if the class code range is between
400 & 499, etc.

I can do this very easily with a pivot table, but I need to copy these
values to a new sheet so I need to make sure they're in the same cell every
time it is updated.