International investors are fleeing the Malaysian market as Prime Minister Najib Razak attempts to ride out a political scandal that is threatening economic stability. The equivalent of about $4 billion has been taken out of the Malaysian stock market this year, and the value of the currency, the ringgit, has shrunk by 11% against the United States dollar, the biggest decline among Asian currencies. At the heart of Najib’s credibility crisis are questions about the running of Malaysia’s debt-ridden sovereign wealth fund, 1Malaysia Development Berhad (1MDB), which is overseen by the prime minister.