Quote from: ethersphere on June 13, 2017, 09:24:36 PM

Quote from: Zev777 on June 13, 2017, 02:35:24 PM

I will just start boldly. The Bancor business model is pretty close to a scam. I am sure you will not take my word for it, because this is my first post. In fact, I made this account because I find it bizarre that no one is talking about this. Let's be honest, which one of you truly tried to comprehend their mathematical proof? Not a single person who invested at least, because otherwise they would not have wasted their money. I will try to explain a little.

They collected pretty close to 400k ether. Essentially what they do, is keep .8*400k ETH = 320k ETH to themselves, and call the remaining 80k reserves. They will express this 80k in a different coin, called BNT. They assign 100 BNT to 1ETH that they received. That means there is 500BNT for every 1ETH in the reserves. Essentially, if everyone would want to convert their BNT back to ETH, they would get 1/500 ETH per BNT. Wait you say, in the white paper it says that the starting price of 100BNT will equal 1 ETH! This is true, this is where the mathematics uses a trick to hide what is going on. Their pricing formula, P=R/(S*F) ensures that the first BNT sold will be sold at a 'fair' value, namely equal to the amount of ETH you spent to buy it in the first place. After the first sell, things get worse rather quickly. Let's illustrate this by a little example:

Lets say that 10% of people who own BNT sell it back to ETH via the smart contract. For the initial price we get: P = 80k/(40m*.2) = 0.01. All looks fair. Then after the sell we get 40m*10%*0.01 = 40k, P = 80k-40k/((40m-4m)*0.20) = 0,00556. Ouch, the price almost dropped to half value from the 10% sell-off (this is different if there are many small transactions but I will get to that later).

If people buy the same amount of BNT, this is what happens: P = 120k/(44m*0.20) = 0.01364. The increase in price is not nearly as interesting for the next person. But again, this will be lower for many small transactions.

I created a plot assuming transactions are made in small batches of BNT coins. We find that the BNT value drop VERY quickly when people start selling, and does not rise nearly as fast. Essentially this just makes BNT an undesirable coin. Another weird thing about their system is that it does not consider convexity. This means that big transactions will get very different prices than many small ones. This just does not make sense, but they don't care as they simply took your money.
http://imgur.com/a/f9yLy

If you are still not convinced, consider this. They literally admit to taking 80% of your money. All they give back is some mathematical trick based on 20% of the ether that you gave them. Do you really believe they just generated x5 value out of thin air? Sorry, but math does not work that way. I would recommend getting rid of your BNT asap, or you end up all the way on the left side of the graph. I am sorry that this news comes a bit late for some of you... I didn't read their methodology until last night Sad

Maybe now you can start to add up why the ICO was strange in various ways.

As final words, don't just believe whatever I say. Think about it for yourself. I gain nothing by convincing you of whatever I write here, I am simply sharing thoughts.

They do factor in the size of transactions when calculating liquidation price. Here's a quote from their whitepaper:

"The above formula calculates the current price, however, when a purchase or liquidation is
executed, the effective price is calculated as a function of the transaction size. The calculation
can be described as if every transaction is broken up into infinitely small increments, where each
increment is changing the smart tokens supply, reserve balance, and thus its price."

The scenario where one person sells off a large amount to get a good price (at the expense of others) might not really happen since they are using "effective price".

Yes, I indeed see that they bothered to solve the curvature issue. Thank you for commenting on content. The main issue is that the coins are backed by a small portion of the investors money though.