Interactive Brokers 的一些下单类型

SNAP to Market (SNAP MKT)

在 Interactive Brokers 的网站上是这样解释 SNAP MKT 单的：

The Snap to Market (SNAP MKT) order is similar to a pegged order, as the original order price is determined by the current bid/ask plus or minus an offset. But unlike the pegged order price, the "snap to" order price doesn't continue to peg as the price moves.

Sell order price = Bid price + offset amount
Buy order price = Ask price - offset amount 

peg 这个词在金融中经常用，在这里，它的英文解释是：

to keep prices, salaries, or the amount of something at a particular level, often in relation to something else

比如：

The Hong Kong dollar has been pegged to the greenback since 1983, and trades at a tight band of $7.75 to $7.85 Hong Kong dollars per U.S. dollar. When it veers too close to either end, the city's de-facto central bank — the Hong Kong Monetary Authority (HKMA) — would intervene by selling or buying the currency.

IB 里默认的 offset 是 0.01，也就是一分钱。比如股票 X 当前的 bid price 是 17.51，ask price 是 17.79，默认下 SNAP MKT 单子，其实就是如果卖单，那么卖价 17.52；如果买单，那么买价 17.58。我个人认为这没多大意义。如果我真的要买一只股票，我一般会把 spread 拉得更大一些，而不是缩得很小。

还有 Snap to Midpoint (SNAP MID)，它是这样设定买价和卖价的：

Sell order price = Midpoint of the Bid/Ask price + offset amount
Buy order price = Midpoint of the Bid/Ask price - offset amount

还有 Snap to Primary (SNAP PRIM) ，它是这样的设定买价和卖价的：

Sell order price = Ask price - offset amount
Buy order price = Bid price + offset amount

SNAP PRIM 符合我喜欢的那种操作，对我有点用。

这些 SNAP TO 的单子都是与当前的 bid/ask price 挂钩的，不会聪明的随着 bid/ask price 的变动跟着变动。

+++++

IB 大约在 2016 年推出了 Adaptive Algo （自适应算法）下单。

MKT ORDER 通常会快速成交。非 MKT ORDER 可能会提供更好的价格，但可能需要很长时间才能执行，甚至可能无法成交。怎么办？IB 就推出了 Adaptive Algo。Adaptive Algo 旨在实现两全其美。

The Adaptive algo order type combines IB's smart routing capabilities with user-defined priority settings in an effort to achieve a fast fill at the best all-in price. It can be used as either a market or limit order.

The Adaptive Algo is designed to ensure that both market and aggressive limit orders trade between the bid and ask prices. On average, using the Adaptive algo leads to better fill prices than using regular market or limit orders. This algo order type is most useful to an investor when the spread is wide, but can also be helpful when the spread is only one tick.

它有三大特色：

1. Most useful when the spread is wide, but could also be helpful when the spread is only one tick.
2. Works with any quantity. The adaptive order will automatically break large orders into smaller chunks to avoid overwhelming the market.
3. Easy to use. Just set the buy/sell action and order quantity, then select the algo from the order types list. 

对 Adaptive Market Orders 和 Adaptive Limit Orders 的介绍及具体操作请看 IB 网站指南。