Since When Was BU An Offical Grade?

Since some coins are sent in by the thousands (or hundreds...or whatever), it is cheaper for the sender to have his/her coins graded BU without the grader going through the trouble of giving a technical grade to each coin in the lot.

Hope that helps.

I have heard of the mass grading done by the TPGs, so they don't bother with putting down the definitive grade with numbers. To reduce costs for the customer.

This is what I've seen them stand for:
GU = Gem Unc
CU = Choice Unc
U = Unc
CAU = Choice Almost Unc
AU = Almost Unc

I think PU would stand for Proof Like Unc?

I'm surprised they don't use BU anymore. And I used to read that CU is the same as MS-63.

From an article in COINage magazine;
"After reading coin descriptions such as semi-proof and practically uncirculated, we wonder what will be next.
The article went on to suggest a few more categories.

WU - was uncirculated

Superb except for slight wear, trifling holes, dents, scratches and gouges.

SU - Slightly uncirculated.
and
Made in same mint as a proof