Although I sure this topic has been covered, a scan of the forum failed to turn up a solution. So...,
Once upon a time while exploring KMyMoney options, I created an 'Investment' account (I actually created three or four 'Investment' accounts). I don't believe I every entered data/transactions in any of these. At some point I decided to scrap that plan, and attempted to delete the accounts. All but one deleted cleanly. The 'Delete account...' option for this remaining 'Investment account' is greyed out. The transactions listing is empty. As others have mentioned, there are likely some 'links' to other KMyMoney entries that are preventing me from deleting. However, thus far, I have been unable to identify what is preventing me from deleting this account. Any help and/or suggestions would be appreciated.

The first thing I would check is whether there are any stock/security accounts within that investment account. Open the ledger for the investment account, then go to the Investment View to check.

Thanks ostroffjh,
That was it. I've been staring at the blank transaction page while I had a single entry hiding on the investment page.