Saudi Arabia’s crown prince and a US private-equity firm run by Barclays’ former chief executive are among investors preparing to invest $1bn or more into Credit Suisse’s new investment bank, people familiar with the matter said.

Crown Prince Mohammed bin Salman is considering an investment of around $500m to back the new unit, CS First Boston, and its CEO-designate, Michael Klein, some of the people said. Additional financial backing could come from US investors including veteran banker Bob Diamond's Atlas Merchant Capital, people familiar with that potential investment said. Credit Suisse previously said it had $500m committed from an additional investor it hasn’t named.