Take context from the input text and decide on the accurate relationship between 'iShares' and 'BlackRock' from the options provided.
Options: location of formation, product/material produced, 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