Bittrex has just released the following announcement.
Removing stale orders: Effective today, Bittrex will be removing orders that are older than 28 days. As we’ve communicated in the past, many of these orders have no reasonable expectation of being filled and clog the order books.
Raising the minimum trade size: Within the next 2 weeks, the minimum allowable trade value for orders will go from 50,000 Satoshi to 100,000 Satoshi. We will also require a minimum trade quantity on a per market basis.
Creating minimum tick sizes: Within the next 2 weeks, on a per market basis, we will be instituting minimum tick sizes that are based on the current price of the market. The target is to have minimum trade sizes that are near 0.1% of the current price. The current minimum tick size is 1 Satoshi. For example, Ethereum trades at 0.0577 Bitcoin. Bids and asks can only be placed in 0.0001 increments. So the next levels allowable levels on the order book will be 0.0576 and 0.0578.
A general statement about market manipulation tactics: Bittrex actively discourages any type of market manipulation, including pump groups. Consistent with our terms of service, we will suspend and close any accounts engaging in this type of activity and notify the appropriate authorities.