No, but you can do this: Select all the text except for the first < and the last >. Select a very small font size. The style's specified for the < and > characters will be what you see in browse mode and now you can put your merge field inside a much smaller text object.
Another trick in fileMaker 12 or later is to place the merge field inside a tab control and use the tab control to "clip" the text object to the desired smaller dimensions. To do that, place a table control on your layout and size it wider than your merge field. Drag the merge field into the table control and release the mouse button. Drag the tab control a few pixels to be sure that the merge field moves when the tab control moves. Then resize the tab control down to the desired dimensions that you want for your merge field.
A third trick is to leave the merge field transparent, but use button or field object placed behind it to show the desired fill color.