Hive account@appreciator is the second biggest bid-bot by vote value at this moment. It is also hard to audit. As noted in the last post (https://busy.org/@verodato/the-return-of-the-bid-bot), we can always verify with certainty what are the delegators to an account. That’s because the delegation transaction is registered in the Steem blockchain with an amount, a sender account and a receiver account. So you can easily check what accounts delegated to a bid-bot. But interest payments are made via a general purpose transaction of transfers of funds between accounts. It is up to the bid-bot to register in the interest payment memo field what such transfers are. A way to estimate interest payments, when they are not labelled, is searching for all the transfers from the bid-bot to the accounts that are delegators to the bid-bot. Keep in mind that we could overestimate interest payments if the delegating accounts do other kinds of transfers to the bid-bot account.
The Hive account@appreciator bid-bot has two main delegators that supply most of its capital, as the chart above shows. As I could find interest payments from Hive account@appreciator to 
Hive account@freedom but not to 
Hive account@blocktrades, I had to exclude the delegations from Hive account@blocktrades from the calculations. Otherwise, the implied rate of return would probably underestimate the bid-bot cost of capital. I could not identify the interest payments made before April 2018, even though the bid-bot seems to be running since last year. The results, shown in the table below, were broken into two categories, to underline the different scales of the amounts delegated by the Hive account@freedom account in relation to other delegators. Interest payments and delegations are expressed in USD.
The return of the Hive account@appreciator bid-bot is close to the results found for the 
Hive account@postpromoter bid-bot only for the month of April, and considerably lower after that. It could be that the Hive account@appreciator bid-bot pays interest after some period longer than a day so that it takes longer to show up in the data. For all the difficulties in understanding the Hive account@appreciator numbers, we would ask for a higher rate of return if we were to invest in this bid-bot.
