sailfrog

We use a coding test as a part of the interview process for new developers and it works quite nicely. Note it is just one part of the process, though it can help sway a decision when we are on the fence (I have personally seen it push the decision both in favor of and against a candidate). Also the test is a solved problem, we don't ask candidates to do our work for us :) Lastly we put a 2 hour limit on the test. Depending on what language the solution is submitted in this may result in an incomplete submission which is fine. We don't want candidates to spend tons of time on it (it is pretty easy to tell when someone has disregarded the time limit) since two hours of work is enough material to gauge metrics that we care about.

Until the source site changes the URL, or the URL arguments, or the page structure, or the doctype, or the CSS selectors, or the element ids, or whatever it is you key on to ferret out the content you care about. Scraping data embedded in markup not bound to an API spec is fragile regardless of how "properly" you parse it because there is no guarantee of structural consistency.

The submission was meant to be humorous, sorry to disappoint. No matter how you slice it parsing HTML from a 3rd party site is a major hack, though this does however work nicely (itch scratched). Lastly I have some other ideas for submissions so don't judge this as the worst just yet.

I have been working on this question for a long time and I think most people have been fooled into believing an incorrect answer. My research indicates that it's actually 41.

Because python devs look down on everybody :)

It's a good feature idea (I implemented a similar one in my open source webmail application a few years ago, I called it "freeze folder") but to go as far as "Paradigm shifted. Game changed" is over the top.

I guess it really depends on your definition of irrelevant. Personally I have no problem with candidates who have a storied past, since I seriously doubt they have made as many ill-informed decisions as I have. For some reason though I have a hard time accepting Romney's refusal to release tax returns before 2010 as legit. Maybe I just relate better with the type of candidate that smokes pot than the type that abuses offshore accounts :P

I agree with regard to full disclosure. The unfortunate reality is that what might normally be considered a past indiscretion can shred a potential candidate's chances at success, mostly thanks to the American electorate's unrealistic expectations. I guess it all depends on what you consider an acceptable indiscretion, but without full disclosure you really can't know for sure.

Grunter owns Twitter

grnthphhh!

Regrunts. Brilliant!

I am not a fan of flash orders but a few nit-picks:

- I believe you have to opt in to have your order flashed. You seem to be suggesting this is happening behind traders backs

- Only one market in the US still supports these types of orders. It may have happened hundreds of times while reading your sentence but that is a tiny fraction of executions occurring across all exchanges during that time-frame.

Let's imagine you head over to the DMV over lunch to get your license renewed. Rather than have a line of people being served via FIFO they randomly pick who gets serviced next. Your lunch hour expires before you get your license renewed, meanwhile other customers barely have to wait thanks to the random selection. Rushing back to work you get pulled over ...

Silly example I know but FIFO matching is consistent with this idea of fairness. Without it it's possible that market participants could keep getting jumped by the random selection such that they never get an order execution.

The way I am reading these comments it would seem that HNers are more curious than idolizing. Personally I do not believe that the length of time in which an entity chooses to own a stock makes that entity inherently bad or good. It is not unreasonable to think a fast execution could make a position unprofitable if delayed by minutes, and I fail to see how that is doing anything wrong.

Insofar as Nanex is concerned remember they are attempting to sell you a product, so be aware of their motivations before swallowing any unsubstantiated assumptions. With that said from what I have seen their charts are accurate but the interpretation of what they mean is sometimes a bit dramatic :)

I can't speak directly to the BATS IPO debacle but I can say that when the NBBO in a symbol is locked or crossed (market speak for the bid and ask being the same or being inverted) matching engines can ignore the NBBO. This results in trades being executing at prices all over the map and can explain how a stock can go from $15 to $1 almost immediately.

I'm not sure reg NMS allows this. Registered exchanges publish protected quotes that other venues are not allowed to trade through.

Zerohedge can be entertaining but the objectivity of it' conclusions is dubious at best. As already stated in the OP, HFT firms place and cancel orders quickly. These charts show this. How exactly is that defrauding anyone? Aside from stating that it does, the article does not explain how. Let's also keep in mind that pretty charts insinuating wrongdoing with a catchy title on a highly trafficked website like ZH is pretty sweet marketing for a company who sells market data products.

Hastymail

"But HFT looks to me like they're just sucking little pieces out of everyone else's trades, while providing no value to society."

This suggests that market participants of any type provide "value to society". Their is only one reason any entity participates in the market, and it has nothing to do altruism, and everything to do with making money for themselves or their clients. Capitol allocation to companies going public is over once the shares are issued via the IPO auction. No transaction on the secondary market results in any money going back to the company that issued the shares. So how does the length of time a firm holds onto a stock before attempting to realize profits define whether or not they provide value?

The common way transaction fees are handled in US equity markets is called the "maker/taker" model. When a participant adds liquidity to the exchange order book, AND that order is executed, they are given a very small rebate per share (they are the "maker"). The other side of the order, the firm who "removed" liquidity from the order book, is charged a very small fee. The difference between the rebate and the fee is the spread the exchange earns for executing the trade.

Note that not all orders that add liquidity qualify for rebates, the rebate may depend on particular order properties as well as the way in which the trade executes.

The rebuttal at ritholtz.com is largely propaganda as well. It was penned by the brokerage firm Themis Trading who has been on a crusade against private exchanges, HFT, reg NMS, and pretty much any change in market structure that could negatively impact their business model. Not only that but the post simply lists properties of the equities markets and implies they are bad. For example:

"-the IOI’s that dark pools send to each other"

If IOI's are bad, why exactly are they bad? The post fails to explain the "why" for any counter argument it presents.

One additional rational not previously mentioned for multiple exchanges is redundancy. Reg NMS allows trading venues to match orders of listed securities from other markets. Because these markets compete as liquidity centers it behooves large market participants to have direct connections to all of them. If the NYSE has technical problems (this happens more often than you may realize, to all the exchanges) trading in NYSE listed securities continues unabated on the other platforms.