Simon Property Group Inc.’s plan to invest in bankrupt rival General Growth Properties Inc. raises antitrust concerns that would hurt the mall owner after it reorganizes, Brookfield Asset Management Inc. said. A plan by Brookfield and its partners, Fairholme Capital Management LLC and Pershing Square Capital Management LP, to bring General Growth out of Chapter 11 bankruptcy is less risky than the competing proposal by Simon, Brookfield Chief Executive Officer J. Bruce Flatt said in a letter to General Growth executives. Flatt said his group won’t proceed without being issued warrants that Simon has excluded from its offer. “We believe that a significant toe-hold position by GGP’s largest direct competitor will be a material ongoing impediment to the prosperity of the company,” Flatt said in the letter.