Complex sentence: In 2006 the company acquired 22.0% of "Unión Fenosa" (raised later to 45%), a leading utilities business, and in 2011, Grupo ACS raised its stake in Hochtief to 50.16%, effectively acquiring the company.
Split into simpler sentences: In 2006 the company acquired 22.0% of "Unión Fenosa" (raised later to 45%), a leading utilities business. In 2011, Grupo ACS raised its stake in Hochtief to 50.16%, effectively acquiring the company.