And they have promised not volatile market. 5%

from 1$ -> 70$ -> 30$. Serrously ? looks like algo is not working
You need to do some finer reading...
https://medium.com/minecoin-blog/minexcoin-monthly-report-1-hit-the-top-675ab5b48fa1This was posted yesterday.
Another question which was asked in the community several times was What will be with the price after $20 high and what does the MinexBank do with fluctuations similar to December hits?. According to MinexBank Memorandum, our algorithm needs three months for a final calibrating and before reaching this point the price will depend on the market like its happening now. So if the market would think that the MNX price should be much higher than it claimed in Memorandum, it will raise. Also, it must be said that, accordingly to our White Paper, Minexbank would correlate the price within 5% range from the cost based the previous days closure price.
The 20$ price was the first basic point set in our Memorandum, says Boris Shulyaev, CEO of MinexSystems. But if you read this document closely, it mentioned that price can differ highly and will set on the mark which market established itself. However, with the price and volume growth, well see fluctuations reductions.
The algo is accounting for "previous day's closure price" as stated in the quote.
They really need to remove that $20 statement on the bank page, it's very misleading.