The higher this ratio is, the more invested hedge fund managers are, as they typically buy puts on these broad-based exchange-traded funds to hedge long equity positions as they accumulate shares.
Long-time readers know that when this ratio is rising, it has typically been a sign that hedge fund managers are accumulating equities and buying put options on these broad-based ETFs to hedge their long positions.
Hedge funds which bet that Japan's deteriorating debt-to-GDP ratio would eventually cause its bond yields to soar as the price of bonds dropped have been repeatedly disappointed.