There are cases in some jurisdictions where 'privilegierte Aktie' is indeed equivalent to 'Vorzugsaktie' ie a whole class of shares with preferred rights to dividends/interest/surplus on liquidation etc:

http://uk.reuters.com/investing/quotes/keyDevelopments?symbo...

But this is not usually the case in the US or UK nor, I think, in Germany. Here there is typically only a single 'privilegierte Aktie' which is not equivalent to a 'Vorzugsaktie' because it typically does not have any preferred rights and indeed will often not share in dividends/interest etc at all (although it may do).

It is usually created for a specfic purpose, most frequently to grant the holder an overriding right of consultation or veto or blocking shareholding percentage in certain circumstances, classically where governments or state bodies retain an interest for national security or other reasons but also eg where a founding shareholder is commercially linked to the business and wishes to have a say in some aspects of how it is run.

'der Bund plane den Einstieg mit der privilegierten Aktie – die mit einem Vetorecht bei Entscheidungen über Veränderungen der Eigentümerstruktur verbunden ist'
http://www.handelsblatt.com/News/Unternehmen/Industrie/_pv/g...

'Zusätzlich habe Wintershall eine privilegierte Aktie ohne Stimmrecht am Gründungskapital von SNGP erhalten und sei folglich mit 35% am wirtschaftlichen Erfolg von SNGP beteiligt.'
http://www.finanztreff.de/ftreff/kurse_einzelkurs_news,b,100...

This is sometimes called a 'privileged share' but I would say that is a lazy translation:

'http://www.strateji.com.tr/scripteng/rapor_detail.asp?rapor_...

The usual English term is a 'special share' or 'golden share' though the latter tends to be used only where governments are involved:

'The MOD also retains the special share in QinetiQ in order to protect UK defence'
http://www.mod.uk/DefenceInternet/FactSheets/ModAndQinetiq.h...

'The effect of the special share was to prevent any change to the 15% limit without the consent of the Secretary of State.'
http://www.scottishpower.com/InvestorNews2_773.htm

'The Special Share is designed to protect the reputation of the "J. Rothschild" name.'
http://investor.sjp.co.uk/sjp/ne/news/releases/pr2002/2002-1...

'I am aware that the “golden/special” share structure was necessary for its past relationship with the former Chairman of Guangxi Yuchai Machinery Co., Mr. Wang Jianming'
http://www.seekingalpha.com/article/39506-an-open-letter-to-...

'the Reuters Founders Share Company, which controls a special share in Reuters, has resolved to support the Transaction.'
http://www.finextra.com/fullpr.asp?id=14944

'RE1 in its personal capacity has been issued with an A Special Share (and has rights under the Management Services Agreement) which entitles it to appoint the directors constituting up to 40% of the DIHL board'
http://www.duet.net.au/duet/management/corporate_governance_...

http://en.wikipedia.org/wiki/Golden_share