Alpha Problems With Render Textures

I'm trying to render an image overlay with an alpha channel using a compute shader and render textures. I don't believe there to be a problem with the compute shader because everything uses float4's. However when I get back my rendered images with render textures, there is no alpha between 0, and 1. If the alpha is 0, the overlay is completely transparent, and if its 1 it is fully opaque. The render textures are initialized with a format of ARGB32 and the overlay texture (texture2D) is initialized with the same convention. All colors are handled with float4's in the compute shaders. Any advice on what the problem is here?