Asian stocks fell for a second straight day, today, and the cost to insure against bonds losses rose after credit-rating downgrades of Greece and Portugal fueled concern about sovereign defaults. Concerns about Europe intensified when global rating agency Standard & Poor's yesterday downgraded Greece's debt to junk status and hit Portugal with a two-notch rating cut. Greece has already admitted it can't pay debts due shortly and has asked for a bailout from European neighbors and the IMF. So Japan's Nikkei 225 index plunged 2.6%; Hong Kong's Hang Seng index slid 1.5%; China's Shanghai Composite index slid 0.3%; South Korea's KOSPI slipped 0.9%; and Singapore's Straits Times index fell 2%.European equities also extended losses. Key benchmark indices in France, Germany and the UK were down by between 0.4% and 1.5% in intra-day trade, today.