This would probably depend on whether your hyperlink element is, in css terms, a 'block-level-element' or an 'inline-element'. The layout engine renders these two kinds of elements differently. A block element is the easiest to understand and it's margins are easily manipulated. However, a hyperlink, which resides within a paragraph is most likely an inline element, which means that it's width, height and margins are determined by various things.

To answer your question correctly, it would be nice to know if your hyperlink is part of a some text or if it could be seen as a block of it's own. Also we would need to know if you want to manipulate the vertical or the horizontal margins.

In case you wanna experiment by yourself, you may try using the css property 'display' to change the element from an inline element to a block element, and then setting the margins:

<a href="..." class="myHyperlink" >Click here</a>
a.myHyperlink
{
 display: block;
 margin: 5px;
}

/Jakob