Its fund managers carried out two huge derivatives deals in 2008 and 2009, to stop the fund becoming insolvent if share prices fell further.
But the vitally important deals were carried out without the explicit approval of senior directors.
The FSA said the firm's supervision had been "unclear and inadequate".
The regulator did not dispute the merit of the two deals, which affected the investments of 114,000 life insurance and pension policies.
http://www.bbc.co.uk/news/business-19994565