RE: Tilton5 Aug 2014 16:28
Graham,
I hadnt realised quite how naive you were on investing, so I will take it easy with you from now on.
If you buy or sell shares, you have to trade with another counterparty, almost certainly a market-maker if you deal online. The market maker is there do as the name says on the can i.e make a market in the shares. He will make a bid and an offer price, and will deal on those prices up to a certain amount of shares. He buys and sells shares at risk, unless of course he has business the other way and can make a profit from the two-way trade.
It really is as simple as supply and demand for the majority of the time, but other influences will take hold, especially around results time, and other important announcements. The market-maker will look to keep his books balanced much of the time, and hope that for every buy he makes, he can find a corresponding seller. That is why this situation is most unusual, and intriguing.
If you were to buy shares now, the market-maker you bought them from (there are 5 MM's in PEG) might already have them on his book, or he might go short to you, hoping to buy them back later at a lower price. That is the risk the MM takes.