This is text _{with a sub} next to a floated div. And here is some more text to act as fill to wrap to see what happens at user large fonts or where there is naturally a lot of text. The line height of the .wrap container confuses IE in relation to the sub. You can fix by the often used method to fix float bugs in IE by giving the wrap container a width or a height, you can do this without letting other browsers see this. In my opinion, the best fix is by not messing about in the first place with line-height. Either don't mention it or at least don't let IE *see* you mention it.