How to find new accounts come in with Match function.

Hi all,
Hope you all had great holidays.
Thanks in advance for your help.

Basically, we have a list of accounts that we can export from our data base, and everyday we have new accounts transferred into our data base system. I need to figure out which accounts are transferred over in a day-to-day basis. Of course, it's easy when we only have 10 accounts, but a number of accounts have been increased dramatically, and I figure I need to find an efficient way to do this.

Please take a look at the attached spreadsheet. From A2:A15, all accounts from yesterday, and from B2:B20, all accounts from today, we can easily see that some of accounts are just transferred over. Is there any way that I can use some formula to make this easy?

Thanks again.