Niall Ferguson knows a thing or two about bubbles, having examined at least eight in The Ascent of Money, his thorough analysis of the financial world.
River & Mercantile's Alex O'Reilly has his highest weighting to the US relative to history as a result of low valuations in the country.
Threadneedle's Cormac Weldon has reduced his fund's allocation to banks after being hit by consolidation among cyclical stocks earlier this year.