There's nothing official available online, but the following chart seems accurate:
Code:
Fare Type ANA Booking Class United Booking Class
Premium Normal Fare S F
Premium Tokuwari A C C
Premium Tokuwari B D C
Premium Tabiwari 28 D C
Premium Shareholder's Discount S C
Premium Disability Discount S F
Normal Fare Y Y
Round-trip Fare Y Y
Shareholder's Discount Y Y
Disability Discount Y Y
Nursing Discount Z Y
Shuttle Round-trip B Y
Business Ticket E Y
Business Repeat E Y
Tokuwari A B M
Tokuwari B Z M
Tokuwari C H M
Tabiwari 28A V M
Tabiwari 28B W M
Tabiwari 45 L M
Tabiwari 55 K M
Specified Connection Discount Z M
Connection Tokuwari Q M
Connection Tabiwari L M
Issho-ni Mile Wari K M