I'm an absolute beginner to investing. I'm currently looking into the "iShares Core MSCI World UCITS" ETF tracking the MSCI World Index.
The iShares Website shows how over the past 5 years the ETF's value moved exactly the same as the underlying index, increasing by 31%:
Business Insider contradicts this, saying the index only went up 23%:
I looked up the ETF's identifier (IE00B4L5Y983) on my bank's website. Their 5-year chart shows a price increase from 45 to 71 EUR, about 57%:
What is going on here? I know there will be slight inaccuracies between different exchanges and the ETF versus the actual index. But 23% and 57% is a huge difference!