since its inception in 1881, mgex has been the principal market for hard red spring (hrs) wheat â first as a cash market, then futures and options. mgex now offers new index-based contracts in addition to their flagship hard red spring wheat. index futures and options contracts are offered on hard red spring wheat (hrsi), hard red winter wheat (hrwi), soft red winter wheat (srwi), corn (nci) and soybeans (nsi). these indexes are calculated daily by data transmission network (dtn), an omaha-based electronic commerce and information services company.