NumberFormatLinked Property [Excel 2003 VBA Language Reference]
True if the number format is linked to the cells (so that the number format changes in the labels when it changes in the cells). Read/write Boolean.
Example
This example links the number format for tick-mark labels to its cells for the value axis in Chart1.
Charts("Chart1").Axes(xlValue).TickLabels.NumberFormatLinked = True
Applies to | DataLabel Object | DataLabels Collection Object | TickLabels Object