Investment funds are generally subject to Form D filings since they don't do "public" offerings as defined by the SEC. So yes, billion dollar hedge funds do file for raising massive amounts of money.
One more note, "Amended Filings" will show the highest amount of money raised to date. To determine how much money was raised recently, you need to subtract the underlying "New" filing and any subsequent amended filings. The SEC's data structure makes it difficult to get amounts of all the referenced filings to do this automatically (basically to 'diff' the filings) so I leave it to readers to do. Example: http://www.formds.com/issuers/mount-vernon-securities-lendin...
One more note, "Amended Filings" will show the highest amount of money raised to date. To determine how much money was raised recently, you need to subtract the underlying "New" filing and any subsequent amended filings. The SEC's data structure makes it difficult to get amounts of all the referenced filings to do this automatically (basically to 'diff' the filings) so I leave it to readers to do. Example: http://www.formds.com/issuers/mount-vernon-securities-lendin...