GMAC bonds rallied on Wednesday as investors anticipated an announcement from the US government that it will invest another $7bn in the company, through which it could take a majority stake, in an effort to shore up the automotive industry.

GMAC is the last of the 10 leading US banks that were deemed by the government to have capital shortfalls to reveal its plans for raising that capital. The other banks, as well as some that did not have capital shortfalls, have offered tens of billions of dollars in equity and debt.