It is quote stuffing or latency arbitrage. The fake quotes are offered and then pulled away before they are filled which can sway the price. Meanwhile an insider who knows what the computer is doing can buy or sell depending on the direction of the equity. Zero Hedge has documented thousands if incidences since 2009.
The court case against JPM Chase for manipulating the sil-ver market had these charges, among others, in it with evidence that they swayed the silver price with this method meanwhile capitalizing on it. But, of course, the case was dismissed.
The sil-ver market is easily pushed around like this since it is such a tiny market. When volume is light, mainly between 6 and 7 PM EST Sunday or between 6 and 8 each morning, there are multiple cases whereby silver and consequentially, or as well as, gold plummet(big banks are chronically short), decoupling from oil and inversely the USD, without corresponding news. The JPM court case charges actually located the venue from which the quotes came from. It was a place solely set up for this purpose.