Simon Property Group Inc. added four backers to its proposal to help rival mall owner General Growth Properties Inc. emerge from bankruptcy, increasing the plan’s total investment by $1.1 billion.

ING Clarion Real Estate Securities, Taconic Capital Advisors, Oak Hill Advisors LP and Deutsche Bank AG’s RREEF unit will join the plan, Simon said yesterday. The investments would be on top of the $2.5 billion pledged by Indianapolis-based Simon and $1 billion from New York hedge fund Paulson & Co.