The Net Asset Value for closed end funds (which often trade at a discount) such as RA, OPP, EVV, KIO etc. is a key metric I use in evaluating my trades. Bloomberg provides this data as well as sites such as www.cefa.com. Other closed end funds such as ECC trade at a huge premium (so I avoid them) - I would love to have that as an easy reference when looking up a closed end fund - related to that is the UNII for the funds which indicates if they are going to be able to sustain their dividend. That is more difficult to find but both would be very valuable.