MAXVISIBLE

MAXVISIBLE(rgeValues)
Returns the largest value from the visible, non blank cells.

REMARKS
* This function excludes hidden cells caused by AutoFilter, Grouping or that have been Manually Hidden.
* You can use the built-in MAX function to include hidden cells.
* You can use the user defined MAXAVISIBLE function to
* You can use the user defined MAXVISIBLEIFS function to
* Similar to the user defined functions AVERAGEVISIBLE, COUNTVISIBLE, MEDIANVISIBLE, MINVISIBLE and SUMVISIBLE

For instructions on how to add this function to a workbook refer to the page under Inserting Functions