=SUBSTITUTE(MCONCAT(IF(SUBTOTAL(3,OFFSET(A3:A10,RO W(A3:A10)-MIN(ROW(A3:A10)),,1)),","&A3:A10,"")),",","",1)

which you need to confirm with control+shift+enter instead of just with
enter.

carl wrote:
I use MCONCAT (Laurent Longre's MOREFUNC.XLL). I often need to filter my
spreadsheet and work with only a portion of the data. I was hoping there was
a way to use the MCONCAT to concatenate only the "visible cells".

My spreadsheet looks like this:

ColA ColB
AB 123
CD 456
EF 123

If I filter ColB down to 123, I would like the MCONCAT to concatenate ColA
Values AB and EF.

Thank you for thinking about this.

Best Regards.