Nisam sasvim siguran, ali mislim da je u pitanju "penziona osnova", takle osnovna svota koju penzioner prima svakog meseca, a ostalo su "dodatci"...

IF THIS IS YOUR CONTEXT: pre•mi•um \"pre-me-em\ noun [L praemium booty, profit, reward, fr. prae- + emere to take, buy — more at redeem] (1601)
1 a : a reward or recompense for a particular act
b : a sum over and above a regular price paid chiefly as an inducement or incentive
c : a sum in advance of or in addition to the nominal value of something <bonds callable at a premium of six percent>
d : something given free or at a reduced price with the purchase of a product or service
2 : the consideration paid for a contract of insurance
3 : a high value or a value in excess of that normally or usu. expected <put a premium on accuracy>
2premium adjective (1844)
ALSO:
PRVOKLASAN, IZUZETAN: of exceptional quality or amount; also : higher-priced

..ili agio

"Premium" bi ovde bila "premija penzionog/penzijskog osiguranja"

Premija je suma koja se periodično (mesečno, kvartalno, itd. u toku nekoliko godina) ili jednokratno uplaćuje u penzioni fond. Tako akumulirani kapital se ispunjenjem nekog od penzionih uslova isplaćuje u vidu mesečne penzije.

Prema tome:
premium pension = premijska penzija / penzija sa (višegodišnjim) plaćanjem premije