Analyze the relationship between 'iShares' and 'BlackRock' within the context of the input sentence.
Options: product/material produced, location of formation, owner of, operator

Trading in BlackRock Inc.’s iShares ETFs was paused more than 200 times, while those sponsored by State Street and Vanguard were halted more than 70 times, according to data from Nasdaq OMX Group Inc.
operator