cCan you please interpret in detail the CPI values? why are they negative?

QUOTES & COMPANIES IQ Real Return ETF CPI (U.S.: NYSE Arca) VIEW ALL COMPANIES 1D AT CLOSE 3:28 PM EDT 07/30/20 5D 1M 3M YTD 1Y 3Y $ Volume 5,050 $27.3011 USD -0.0125 -0.05% 65 Day Avg Vol 2,189 $27.3 1 Day Range 27.26-27.3011 $27.2 52 Week Range 25.10 - 28.52 (03/23/20 - 12/27/19) $27.1 Jul 24 Jul 27 Jul 28 Jul 29 Jul 30 ADVANCED CHARTING COMPARE - Open 27.27 Prior Close 27.3136 (07/29/20) 1 Day CPI-0.05% DJIA -0.85% S&P 500 -0.38% Screenshot Nasda