Holcim Chief Executive Jan Jenisch on Monday described his company's North American operation, which the Swiss building materials firm plans to spin off next year, as a "rock star business." Holcim on Sunday announced it was spinning off 100% of its North American business in the biggest shake-up at the cement maker since it bought French rival Lafarge in 2015. The division, which now has sales of $11 billion has been a star performer for Holcim in recent years, increasing its sales by an average of 20% per year.