Why does account reconciliation still dominate month-end close timelines at large firms?

At scale, reconciliation seems to consume a disproportionate amount of time during close. Even with ERPs and controls in place, finance teams still spend days tracking small breaks and timing mismatches.

In some teams I’ve spoken with, tools like Collatio Accounts Reconciliation software are being used to take repetitive matching off analysts’ plates, but reconciliation still ends up being a bottleneck when volumes spike.

For those in corp fin or controllership roles, where does reconciliation realistically sit in your close timeline? Does tooling change the dynamic much, or is process the real constraint?