Step 1: Access ACCOUNTS via IX_ACCT_CUST with MATCHCOLS = 1 on CUST_ID. For a typical customer with 3-5 accounts, this returns a handful of rows. - Step 2: The correlated subquery accesses TRANSACTIONS via IX_TRANS_ACCT(ACCT_ID, TRANS_DATE) with MATCHCOLS = 1. Because the subquery needs only MAX(TRA