Complex sentence: During this period, the waterfall was rented indirectly by its owners, Tómas Tómasson and Halldór Halldórsson, to foreign investors; however, the investors' attempts were unsuccessful, partly due to lack of money.
Split into simpler sentences: During this period, the waterfall was rented indirectly by its owners, Tómas Tómasson and Halldór Halldórsson, to foreign investors. However, the investors' attempts were unsuccessful, partly due to lack of money.