I've owned many CEFs in my time, and in my experience tender offers (share buybacks) are way more common that RO's - RO's are only good for existing shareholders if the CEF is trading at a significant premium to NAV - for one at +20%, they're getting $1.20 for $1.00 worth of assets, an excellent deal.
Nobody like dilution, but it's sure better than BK, which is where AMRN would be if they hadn't been able to raise money time after time using secondaries.