High-rise apartment living is being proposed by two rival developers competing to acquire the south half of the downtown block that until this summer was home to Stage Center.

The proposals submitted by Indianapolis-based Milhaus Development and Chicago-based Clayco both envision construction starting soon after the 2015 Spring Festival of the Arts set for next April.

Milhaus, which is already building a $42 million mixed-use development with 329 apartments in Midtown, proposes a 20-story, mixed-use tower consisting of 300 residences, 15,000 square feet of commercial space, and a 450-space garage.

Clayco, meanwhile, is proposing to build four buildings — two as part of the previously announced OGE Energy Center development, and two more on the south half of the block. The Clayco proposal for the south half of the block would consist of a 25-story commercial building and 26-story, 253-unit apartment tower.