In this post I’ll show an alternative that uses XY chart series to free you from the vertical or horizontal lines provided by error bars. The technique is pretty easy. Here is the line chart, unadorned by any labels.
The data you need to label two points is shown below; there’s one set of data and one added series per label. The date and price in the first column correspond to the point where the segment meets the line chart, and those in the second column are where the segment terminates and the label is located. The arrangement allows each added series to use the label as the series name.
Copy the first set of data, select the chart, and use Paste Special to add the data as a new series; repeat for the second set of data.
For each added series, select the point that is not connected to the line series: single click on it once to elect the whole series, then a second time to select the individual point. Format the point to use the series name as a data label. In Excel 2003 and earlier, right click on the point, choose Format, and on the Data Labels tab check the Series Name box. In Excel 2007, on the Chart Tools > Layout tab, click on Data labels, select More Data Label Options at the bottom of the list, and in the Label Options pane of the dialog, uncheck Value, check Series name, and choose the label position you want.
Finally, format the extra series so they look like callout lines. Hide the markers and if desired change the line color to black.