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.
This example is to illustrate the bid/ask spread, with the BID price on the left, and the ASK price on the right. The BID Price: Essentially, the BID is the price at which a buyer or market maker is willing to buy a security. If you owned shares in a stock, say AuthenTec, and wanted to sell, it is the current price at which someone is willing to purchase your shares.