We’ve seen a huge market crash this year and a number of firms reporting portfolio losses. So why were so many big investors crowded into the same trades, and what does it say about investing as a whole? Should investors be playing up to their competitive advantage, or following the crowd to profit from momentum? Steven Abrahams, head of investment strategy at Amherst Pierpont Securities, has written a new book about competitive advantages in investing. We talk to him about how different types of investors place their money and why some portfolios can survive better than others.