Too many outbound link will leak PR juice from that page. It's best to have maximum 8-10 links on a page and try to link them to internal pages only.
Too many outbound links brings you close to a linkfarm. But still, how many links exactly do you consider too many?
Thanks every one for replies. I think this is the reason my blog is not getting PR. I linked some posts to local Stock Exchange for more information. The blog I am talking about is my signature link. So please tell me is it ok to keep these outbound links & not to do it again in future or remove it as soon as possible?
If you link to the sites which have higher PR, I think there can be little harm to Your site. but actually get as many backlinks as you can.
If all your outbound links are do-follow, then having too many links (generally more than 15) will result into what is called pagerank bleeding. Do-follow links will leak your pagerank to other sites. So if you wish to conserve your pagerank, you need to use no-follow tag for outbound links which do not deserve pagerank juice from your site.