Garthwaite points out other key risks that could push equities in different directions.
FORBES: How the S&P 500 Could Plummet by 40% This Year
2.
One of the biggest tail risks, Garthwaite says, is a eurozone break-up, something investors have been worrying about as the debt crisis shows no sign of abating or being fixed quickly.
FORBES: How the S&P 500 Could Plummet by 40% This Year