- UID
- 223391
- 帖子
- 213
- 主题
- 35
- 注册时间
- 2011-7-11
- 最后登录
- 2014-8-7
|
What the heck is "liquidity," exactly...
Yes, I know more-or-less what liquidity means. But the problem is that it’s only “more-or-less.” I hear people talking about “adding liquidity” or “providing liquidity” or “liquidity driven” things like it’s the most obvious thing in the world.
In my mind, I think of liquidity as “the ability to convert an asset to cash quickly at close to the last quoted price.”
A corollary from the purchase side is “the ability to purchase an asset quickly at close to the last quoted price.”
There are several dimensions:
A: The quantity of an asset that gets converted. Converting larger quantities of an asset tends to have a larger impact on price at all levels of liquidity.
B: The speed at which the asset can be converted. The ability to distribute transactions over time reduces the price impact, but it also opens up risk to price changes from other factors in the interim.
C: The discount to the last price. The greater the price impact, the lesser the liquidity.
One version of this view (consistent with practitioners) is that the bid-ask spread is an indicator of liquidity, because if you buy something and immediately want to sell it, the BA spread tells you how much of a hit you must take on the price to turn around instantaneously.
But there are plenty of other times when people talk about providing liquidity that doesn’t really seem to fit into this view, and I wonder what I’m missing. HFT firms, for example, talk about “providing liquidity,” but in fact, that liquidity can disappear instantaneously, so are they really providing it? How are they making money, other than, perhaps, from each other. |
|