BAML also noted big precious metals inflows generally of $2.6bn.
Meanwhile, the bank saw the largest inflows to high yield in 16 weeks and a risk-on shift in fixed income corroborated by the first outflows from treasuries in eight weeks.
Furthermore, there were signs of the bull market unwinding, with outflows from healthcare/biotech in 12 of the past 13 weeks, and Japan and Europe equity funds easing. Equities saw outflows of $2.7bn and bonds recorded "very modest" outflows of $0.2bn.
"European marketing this week corroborates the super-high cash levels revealed in Feb and scarcity of bullish views; everyone, including ourselves, is a "seller into strength" which means risk can squeeze higher short-term into policy events," said the bank.
Flows are nonetheless not close to "full-capitulation" levels; investors increasingly regard policy meetings as a selling catalyst -not a buying catalyst- so selling pressure resumes if policy disappoints, according to BAML.
Emerging market debt funds recorded the first inflows in seven weeks.