For Stephen A. Schwarzman, the co-founder of the private equity giant Blackstone Group, an accounting rule partly explains why the American financial system looks so wobbly these days.

The Blackstone Group posted a $66.5 million quarterly loss on Thursday, and its executives warned that the turmoil in the financial markets may not be over.

The main branch of the New York Public Library will be renamed after Stephen A. Schwarzman, a Wall Street financier, who contributed $100 million to the institution.

The main branch of the library will be renamed after Stephen A. Schwarzman, a Wall Street financier, who contributed $100 million to the institution.