An enlightening article by Ali Ansari in The National Interest describes the Iranian Guards' business interests:
The argument that Iranian politics have become militarized makes the issue far too black and white. In fact, the IRGC has come to be in bed with a hard-line establishment made up of the Supreme Leader Ayatollah Khamenei, Ahmadinejad and his clique, and even some journalists and clerics, meaning that the Right has coopted the IRGC as much as the IRGC has coopted them. This relationship between the hard-liners and the IRGC is long in the making, though it has been made far worse by Ahmadinejad’s arrival on the scene. We must remember this was started by Rafsanjani, when the moves into the political economy of the country were not initiated by the Guards though they have undoubtedly become enthusiastic participants. But what this means is that the IRGC is not a military junta. The Iranian state does not face a military coup in the traditional sense of the term. A more accurate categorization of Iran might be to call it the securitization of the state around the needs of an increasingly bloated business conglomerate, which confuses its own interests with those of the nation. This was in effect not the garrison state Hajjarian had warned about, but instead a mafia state writ large.