Less than two years after he was ousted as chief executive of Citigroup, Vikram Pandit is collaborating with the co-author of the popular "Freakonomics" book series to launch a new consulting business aimed at helping companies improve their cultures and use of technology.

Pandit and his new colleagues have been ringing up bank chief executives and others offering their services. Among the recent recipients of the pitch: Top executives at Deutsche Bank, which is trying to improve its corporate culture amid a number of regulatory and legal problems.