When the credit cycle turns negative it means that funds available to be borrowed begin to contract. Interest rates start to rise, lending rules become stricter and in general it just becomes harder to borrow. When the credit cycle turns positive, it's the opposite - it starts to become easier to borrow.

"Froze up" can mean "become solid," as when water turns into ice. But it can also mean "became immovable." When a computer malfunctions, the picture on the screen stops moving: "my screen froze up." When we experience stage fright, sometimes we "freeze up." "I thought I was prepared, but when I walked onto the stage I froze up. I felt paralyzed. I couldn't move." In the case of financial markets, "froze up" is often used, because it is playing on the terms "liquid." "Liquid," "liquidity," and "liquidation" have financial meanings. Water is liquid. When water freezes up, it becomes ice, which is solid and immovable. In finance, something is liquid when it can quickly be sold for cash. To liquidate something is to turn it into cash, by selling it. For example, stocks are usually liquid. If Google says that the price of Apple stock is $214/share and I own ten shares and I want money, I click a button on a brokerage website and, almost instantly, the stock is sold and I have about $2,140 available in my account. In a financial crisis, a market may "freeze up." There is no liquidity. That means that the "market price" is meaningless, because the fact is that you simply cannot sell the asset at all. Nobody wants to buy it. Perhaps there are people who do want to buy it, but they can't because they don't have any money to buy it with. So you cannot sell the asset--it is stuck in your account, it is immovable, it is frozen.

Imagine a graph of something varying in time. The upward direction on the graph is the "positive" direction. Suppose the variable is steadily growing, increasing, getting larger. As we move to the right, the line rises. We can describe this in many ways. The variable "has a positive trend." The variable is "moving in the positive direction." The line on the chart is going up and to the right. Perhaps it is a fairly straight line. Now suppose something changes. The variable stops growing and begins to get smaller and smaller. Now it is "moving in a negative direction." The line on the chart is going down and to the right. In order to change from going up and to the right, to going down and to the right, the line needs to have a "turn" in it. So, "turns negative" carries two meanings: 1) Direction. 2) Change of direction. The direction is "down." "Turn" carries the second idea that the direction has changed--it was "up" before. The change of direction shows on the chart as a "turn" in the line.

Froze up = stopped working or stopped moving. ("When the robbers entered the bank, I wanted to run, but I was so scared that I froze up and couldn't move). Note: a similar term is "seize up," but that usually refers to a machine.