Foreign investors are excited about the prospect of a new era of growth in corporate Japan and their buying helped the Nikkei share benchmark to scale three-decade peaks earlier this month.

Domestic investors are less confident about the rally, which has lost a little steam over the second half of this month.

Global investors have turned more cautious about European equities, in contrast, as optimism that came from the region beating low expectations for economic growth early in the year fizzled out, and even interest in U.S. stocks is waning after a surge in large tech shares in May.

European equities have seen outflows for the past 16 weeks, and U.S. equities for the past two, according to the BofA report which referenced figures from data provider EPFR.

In the week to Wednesday, there were $1.5 billion of inflows to equity funds, $600 million inflows to bonds and $1.5-billion outflows from gold.

U.S. Treasuries saw their 20th straight week of inflows, the longest streak since September 2011, while commodities logged a seventh straight week of outflows, BofA said.

Optimism towards commodities from the start of this year has petered out as China's economy is getting less benefit from its reopening than many investors had hoped late last year.