The following sources are cited in SAP Digital Futures Issue 31: Virtuous Circles: The Circular Economy Gets Rolling

4.5 Trillion: potential value created by 2030 if organizations adopt circular economy principles more widely.
Peter Lacy and Jacob Rutqvist, Waste to Wealth (Executive Summary), Accenture, 2015, https://www.accenture.com/_acnmedia/Accenture/Conversion-Assets/DotCom/Documents/Global/PDF/Strategy_7/Accenture-Waste-Wealth-Exec-Sum-FINAL.pdf

66%: the amount of consumers willing to pay more for products deemed sustainable.
Nielsen, Consumer-Goods’ Brands that Demonstrate Commitment to Sustainability Outperform Those that Don’t, Oct 12, 2015, http://www.nielsen.com/us/en/press-room/2015/consumer-goods-brands-that-demonstrate-commitment-to-sustainability-outperform.html

4%: the increase in global sales in 2015 by brands with a demonstrated commitment to sustainability.
Nielsen, Consumer-Goods’ Brands that Demonstrate Commitment to Sustainability Outperform Those that Don’t, Oct 12, 2015, http://www.nielsen.com/us/en/press-room/2015/consumer-goods-brands-that-demonstrate-commitment-to-sustainability-outperform.html

$3: amount of precious metals recovered using current recycling methods out of a $16 total used in the average cellphone.
World Economic Forum, Ellen MacArthur Foundation and McKinsey & Company, Towards the Circular Economy: Accelerating the scale-up across global supply chains, World Economic Forum, Jan 2014, http://www3.weforum.org/docs/WEF_ENV_TowardsCircularEconomy_Report_2014.pdf