Cardiac tamponade can occur due to: 1  Dissecting aortic aneurysm (thoracic) 2  End-stage lung cancer. 3  Heart attack (acute MI) 4  Heart surgery. 5  Pericarditis caused by bacterial or viral infections. 6  Wounds to the heart.
Bid vs. ask and why yields matter. With many investments, the concept of bid and ask applies to prices. The bid price is what a buyer is willing to pay for a security, while the ask price is what a seller is willing to accept for the same security. The difference between those two numbers is known as the bid-ask spread, and in general, the narrower that spread, the more liquid the market is.
Whereas, the bid and ask are the best potential prices that buyers and sellers are willing to transact at: the bid for the buying side, and the ask for the selling side. But, think of the bid and ask prices you see as tip of the iceberg prices. That is: The Bid: 13.20 x200 is an indication that there are potential buyers bidding $13.20 for up to 200 shares. Their bids are the highest currently bid; and there are others in line behind with lower bid prices.