Morgan Stanley Chairman John Mack said that banks wanting to participate in the initial public offering of General Motors Co. were being asked about lending lines for the ailing U.S. automaker.

When asked in an interview with CNBC if lending lines would be an underwriting prerequisite, Mack said, "That's certainly part of the discussion."

Deutsche Bank in April lost its underwriting spot on Kohlberg Kravis Roberts & Co.'s IPO of Dutch semiconductor company NXP Semiconductors because it refused to renew a line of credit for the company.

GM is moving toward an IPO after the U.S. government acquired 61 percent of its shares in a $50 billion bailout of the carmaker, which emerged from a government-sponsored bankruptcy last July.

Canada and the province of Ontario own nearly 12 percent.