BNT maintains a Reserve of ETH to obtain high liquidity. You can check reserve balance and how funds are flowing into it here.
https://etherscan.io/address/0xD76b5c2A23ef78368d8E34288B5b65D616B746aE#tokentxns
Following transaction means that BNT is issued out of the reserve and 4.9 ETH went into the reserve. Transaction link will give more details about how many BNT were issued.
Following transaction means that 16.077179087751796628 ETH was taken out of reserve and it's equivalent BNT went into the reserve.
Total reserve balance is currently (25.29K + 70K) ETH.
70K ETH of the reserve was stored by Bancor in a different multi-sig wallet.
You can check the following spreadsheet to find out how BNT price will change according to reserve balance.
You cannot pump and dump BNT, because of reserve. After BNT was introduced on Bittrex, it was volatile for few mins. Then it became stable.
Unlike other ICOs BNT is not a for people that want to get rich quickly. I hope this will be useful for people that want to invest in BNT.