Corporate postal envelopes - can we preprint return address at the back of envelope, instead of at front?

I'm printing corporate stationery. My designer is proposing that the return address be printed on the back of envelope for aesthetics. I was told by someone that the US postal service has regulations that return addresses cannot be printed at the back, only on the front. I'm going to the printers this week. Not sure what to do.Corporate postal envelopes - can we preprint return address at the back of envelope, instead of at front?
It is not a good idea to print the return address on the back of the envelope. Aesthetics are a crock.

Think of all of the Fortune 500 companies that send out mail. Think of any other number of major corporations worldwide. Doesn't your designer think that those image conscious companies care about aesthetics also? But they also know the value of efficiency and propriety of design. That is why they always put their address on the front of the envelope.

Tell your designer that only 80 year old ladies put their return address on the top middle backside of the envelope.

nada bluebook

bbq