When large blocks of ETF shares are redeemed, individual underlying holdings:

$1.$ With the highest cost basis are typically provided to the redeemer

$2.$ With the lowest cost basis are typically provided to the redeemer

$3.$ With the highest cost basis are exchanged for holdings with the lowest cost basis by the redeemer

$4.$ With the lowest cost basis are exchanged for the shares with the highest cost basis by the redeemer