The letter went out as investors are growing increasingly nervous about the company's financial results.
It reached 63 percent on Thursday, which suggests that investors are growing more pessimistic.
Individual investors are growing less nervous as stock prices reach record levels.
But investors grew wary last year, and overseas investment began to slow.
Institutional investors, such as pension funds, grew in number and influence.
After the disclosure, some investors grew worried about other contracts.
Bankers and investors have grown more savvy about environmental risks.
Even if that is true, many investors have grown impatient.
But the investors grew uneasy with their choice of bankers even before they had a deal.
Over time, he said, investors will grow more comfortable that corporate profits are real.