When you create a chart in Excel, the order in which the data is plotted is important. By default, Excel plots data series in the order in which they are added to the chart. But sometimes, you may want to change the order of the data series so that large values are plotted last. This can be especially helpful if your data contains negative values.

To change the order of a data series, follow these steps:

1. Click the chart to select it. This displays the Chart Tools tabs on the ribbon.
2. On the Design tab, in the Data group, click Select Data.
3. In the Legend Entries (Series) box, click the series that you want to move, and then click Edit.
4. Under Series Order, click the arrow next to Value, and then click either Ascending or Descending.
5. Click OK twice.