The SNB was not forced to act by a speculative run. No financial crisis forced its hand, and, in theory, the SNB’s directorate could have held the exchange rate and bought foreign assets indefinitely. But domestic criticism of the SNB’s large buildup of exchange-rate reserves (euro assets) was mounting.
In particular, Swiss conservatives disliked the risk to which the SNB was exposed. Fearing that eurozone government bonds were unsafe, they agitated to require the SNB to acquire gold reserves instead, even forcing a referendum on the matter. Though the initiative to require a fixed share of gold reserves failed, the prospect of large-scale quantitative easing by the European Central Bank, together with the euro’s recent slide against the dollar, intensified the political pressure to abandon the peg.
Whereas economists have modeled financial attacks well, there has been little study of just when political pressure becomes unbearable and a central bank gives in. The SNB, for example, had proclaimed loyalty to the peg just days before ending it. As a result, markets will now hesitate to believe central banks’ statements about future policy, and forward guidance (a major post-crisis instrument) will be much more difficult.