Market chaos has caused BlackRock, Vanguard and State Street Global Advisors to see their assets drop by an estimated $2.5trn, according to the FT.
The world's three biggest fund managers are feeling the effects of a global sell-off in financial markets as US stocks fell into bear market territory after more than a decade of gains and the FTSE 100 suffered its worst one-day drop since 1987.
BlackRock, the world's largest asset manager, has seen assets under management drop nearly $1.4trn to $6trn from a record $7.4trn earlier this year, according to FT calculations. Shares in BlackRock have dropped 28% since their February high, cutting the New York based group's market value to $64bn.
Its American rivals Vanguard and State Street Global Advisors also saw assets shrink. Vanguard's assets reached $6.2trn in January, fell to $5.9trn by the end of February, and are now tracking at about $5.4trn based on recent market falls.
State Street Global Advisors, had assets of more than $3.1trn earlier this year. The FT estimates its assets will have fallen by about $600bn to $2.5trn in the past four weeks, assuming a fall in line with US equity markets.
These three passive management giants - BlackRock, Vanguard, and State Street, the so-called "Big Three" - control 80% of the value of index funds in the US.