Barclays also negative on sustainability of current rally:

Consequently, for the time being we are not inclined to change our tactical asset allocation: we advise investors to remain neutral risky assets, while being underweight European risk across assets. The latter would be offset by higher regional equity, rate and credit exposure to the US and/or Japan and EM, which should serve us well in a short-lived bounce in risk sentiment. While valuations of many risky assets look attractive following the recent sell-off (see, for instance, Reaction to the US sovereign downgrade, 7 August 2011, for an assessment of present US equity valuations), we recommend to stay invested “close to home”, as value at risk is particularly elevated at this juncture and the interplay of macroeconomic momentum and policy-driven events does not provide a clear buying signal for risky assets other than for a very short-term recovery in risk sentiment. Neither would we want to be short risky assets, as decisive policy action, particularly by euro area politicians, if it were to happen, could provide the trigger for a more substantial relief rally. By contrast, while we expect the macro momentum to improve in the course of H2, the effect on asset prices would most likely be modest and gradual. That said, we would review this tactical view should a more credible, comprehensive and timely approach be adopted by politicians in Europe to contain the crisis and address the underlying reasons.