I moved my investments to a new broker and created new accounts in Quicken. The investments started showing up in the account before transactions downloaded. As such Quicken inserted placeholders to reflect the value the account was reporting. When the transactions finally downloaded they showed as a Match to the placeholders.

...except that when accepted the transactions did not populate the values in the placeholders. I learned the hard way that I need to delete the placeholders before accepting the Matching transaction.