Fund buyers have called for more transparency on passive fund costs not contained within the ongoing charges figure (OCF) - even as a price war cuts headline fees to record low levels.
The S&P 500 has risen by 2% overnight as US stocks continue to rally from the lows sustained last week.
The six-year bull market in the US is still viewed with "deep suspicion", despite the wave of supportive factors, says AXA's Dan Harlow.
Shares on Wall Street have recorded the worst three-day streak since 2011 after another sharp move lower overnight, with investors continuing to fret over the end of the US Federal Reserve's bond buying programme.
US stocks posted their largest one-day gain this year as the latest meeting minutes from the Federal Reserve suggest it may adopt a more cautious stance on hiking interest rates.
Markets in the US fell overnight, after the International Monetary Fund (IMF) cut its forecast for global growth for the next two years.
State Street Global Advisors (SSgA) is the latest ETF provider to slash fees on a range of its European products, as passive fees continue to come under pressure.
UK markets opened lower Friday after a tough session in the US where stocks suffered sharp losses on the expectation of an imminent rate hike by the Federal Reserve.