Ask HN and PG: Views on parent companies

I was wondering about parent companies, specifically from an investor's perspective. Companies like Atlassian own a lot of what could be deemed as separate companies (JIRA, HipChat, BitBucket, etc). Say for instance an investor only wants to invest in HipChat. Would Atlassian have a separate legal entity for HipChat that allows that investor to only invest in that product, or is the investor forced to invest in the parent company and all of their products? If you have a lot of products, would you list them on a site like AngelList separately or only list the parent company?