In the event that the partnership agreement of the main fund has been properly developed to take into account the opt-out of AIV parallel investors, the special attributions of UBTI and ECI by those investors for US tax purposes should be respected. Accordingly, tax-exempt investors should not be required to report UBTI because of their investment in the main fund. Parallel AIVs also do not prevent the fund from participating itself in the business or activities of operating LLCs in the United States, in which the fund and its parallel AIV invest. As a result, parallel aivs generally do not fulfill the contractual obligations arising from typical partnership agreements concerning UBTI and CIS, which generally require the complement to have a certain level of effort (z.B. "economically reasonable efforts" or "best efforts") to prevent the Fund from acting in a trade or activity and to avoid the generation of UBTI and ECIs. . . .