A ‘No' vote would significantly increase the odds of Grexit, though some hopes remain that it could be avoided

A 'No' vote would not immediately trigger a Grexit, especially as the chance of new elections still remain, even in this scenario Greek president would most likely resign. Moreover, some form of negotiation may resume. As long as the line of communication remains open and until the Eurogroup and EU leaders make it clear that Grexit is unavoidable, the ECB will maintain ELA funding - though potentially with increased collateral haircuts. Once the political backing is given by the EU leaders, the ECB would start unwinding the ELA funding, trying to implement a managed exit in coordination with the Central Bank of Greece. 

The EU is much better equipped to stem contagion today than in 2011-12, with a QE programme in place, the ESM facilities (the Secondary Market Purchase Programme in particular) and the OMT. Moreover, the direct financial costs are manageable - though Cyprus, already under a programme, is the weakest link. The political contagion is the most significant risk. Limiting this risk will require further steps towards a genuine monetary, fiscal and political union.says Societe Generale.