A silver lining in a G-SII label?

The requirements would be phased in, beginning in 2015, for the higher loss absorbency capital requirement, including top-quality capital needed to cushion financial activities and products deemed to be nontraditional insurance, such as variable annuities, or not insurance at all, such as derivatives hedging. 

However, the positive credit implications for G-SIIs are muted somewhat, Moody's said, by any lack of flexibility the insurers will be subject to under the recommended requirement restraints, hampering their ability to be nimble and independent enough to diversify their earnings and attract investors. 

"In particular, the forthcoming capital surcharge could make G-SIIs less competitive than those not designated as G-SIIs because they would need to raise prices to achieve current return targets," Martinez said. "Such lower returns could also affect G-SIIs' ability to raise capital if investors find them less attractive relative to peers unburdened by the FSB's supervision," she stated in her report.

Moody's has also said that the U.S. domestic designations for insurers that are systemically important financial institutions (SIFIs) is a credit positive.

In June, the U.S. Financial Stability Oversight Council (FSOC) named Prudential Financial (U.S.) and AIG, along with General Electric Capital Corporation (GECC, A1 stable) as nonbank SIFIs.