As I have stated in previous posts, this legislation may impact your company in ways that surprise you.
If your company has never conducted a "unitary" analysis, this is something you need to do and will impact the amount of tax you pay in D.C.
If your company (group of entities) has had a net operating loss in the past or if some entities have losses currently, how you file your combined return will impact the utilization of those losses.
If your company (group of entities) includes holding companies and unincorporated businesses, those entities may be included in a combined return and may cause a negative result.
If your company is planning a big sale, you should analyze your company's structure now to determine if any planning or restructuring can be done.
NOTE: I will be providing a presentation on D.C. Combined Reporting at a CFO Roundtable at Baker Tilly Virchow Krause, LLP's D.C. office on January 23, 2013. Please contact me at email@example.com if you would like to attend.