Appending a colums from 2nd list based on match of company name

Hi

I have a list of company data….

Company A Dec-17-2003 1614.5
Company B Nov-26-2003 399
Company C Oct-30-2003 798
Company D Mar-20-2003 399
Company E Jan-28-2004 600
Company F Sep-06-2002 700
Company G Mar-13-2003 138
Company H Feb-15-2005 42.55
Company I Feb-28-2006 2000
Company J Jan-21-2004 300
Company K Nov-28-2003 1600
Company L May-15-2002 399
Company M Oct-20-2006 495
Company N Dec-10-2002 695

And a list of the companies and a reference ID….

Company A A6UJ9A000FBB
Company B A6UJ9A0005X5
Company C A6UJ9A000FDX
Company D A6UJ9A000F18
Company E A6UJ9A000F0K

DOWN TO ....

Company Z A6UJ7A000J2K

From these I would like to append the reference code to the data for companies that occur in list one. As there are many more companies in the second list it is not possible to do this through sorting.

Any thoughts on which functions to use for this?

Many thanks, James