1) The most popular ETN is VXX, the volatility index ETF. Unlike ETF, ETN is actually an

*unsecured*bond issued by the issuer. This means that the price of the ETN may not just depend on the underlying assets or index. It could potentially depend on the credit-worthiness of the issuer. Now VXX is issued by Barclays. You may think that Barclays is a big bank, Too Big To Fail, and you may be right. Nevertheless, nobody promises that its credit rating will never be downgraded. Trading the VX future, however, doesn't have that problem.

2) The ETP issuer, together with the "Authorized Participants" (the market makers who can ask the issuer to issue more ETP shares or to redeem such shares for the underlying assets or cash), are supposed to keep the total market value of the ETP shares closely tracking the NAV of the underlying assets. However, there was one notable instance when the issuer deliberately not do so, resulting in big losses for some investors.

That was when the issuer of TVIX, the leveraged ETN that tracks 2x the daily returns of VXX, stopped all creation of new TVIX shares temporarily on February 22, 2012 (see sixfigureinvesting.com/2015/10/how-does-tvix-work/). That issuer is Credit Suisse, who might have found that the transaction costs of rebalancing this highly volatile ETN were becoming too high. Because of this stoppage, TVIX turned into a closed-end fund (temporarily), and its NAV diverged significantly from its market value. TVIX was trading at a premium of 90% relative to the underlying index. In other words, investors who bought TVIX in the stock market by the end of March were paying 90% more than they would have if they were able to buy the VIX index instead. Right after that, Credit Suisse announced they would resume the creation of TVIX shares. The TVIX market price immediately plummeted to its NAV per share, causing huge losses for those investors who bought just before the resumption.

3) You may be familiar with the fact that a β-levered ETF is supposed to track only β times the

*daily*returns of the underlying index, not its long-term return. But you may be less familiar with the fact that it is also not supposed to track β times the

*intraday*return of that index (although at most times it actually does, thanks to the many arbitrageurs.)

Case in point: during the May 2010 Flash Crash, many inverse levered ETFs experienced a

*decrease*in price as the market was crashing downwards. As inverse ETFs, many investors thought they are supposed to

*rise*in price and act as hedge against market declines. For example, this comment letter to the SEC pointed out that DOG, the inverse ETF that tracks -1x Dow 30 index, went

*down*more than 60% from its value at the beginning (2:40 pm ET) of the Flash Crash. This is because various market makers including the Authorized Participants for DOG weren't making markets at that time. But an equally important point to note is that at the end of the trading day, DOG did return 3.2%, almost exactly -1x the return of DIA (the ETF that tracks the Dow 30). So it functioned as advertised. Lesson learned: We aren't supposed to use inverse ETFs for intraday nor long term hedging!

4) The NAV (not NAV

*per share*) of an ETF does not have to change in the same % as the underlying asset's unit market value. For example, that same comment letter I quoted above wrote that GLD, the gold ETF, declined in price by 24% from March 1 to December 31, 2013, tracking the same 24% drop in spot gold price. However, its NAV dropped 52%. Why? The Authorized Participants redeemed many GLD shares, causing the shares outstanding of GLD to decrease from 416 million to 266 million. Is that a problem? Not at all. An investor in that ETF only cares that she experienced the same return as spot gold, and not how much assets the ETF held. The author of that comment letter strangely wrote that "Investors wishing to participate in the gold market would not buy the GLD if they knew that a price decline in gold could result in twice as much underlying asset decline for the GLD." That, I believe, is nonsense.

For further reading on ETP, see www.ici.org/pdf/per20-05.pdf and www.ici.org/pdf/ppr_15_aps_etfs.pdf.

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*moving*window to optimize parameters and entering trades only in the out-of-sample period. He also compiled a standalone application from MATLAB that allows any user (having MATLAB or not) to upload quotes in csv format from Google Finance for further import to other programs and for working in Excel. You can download it here: wfatoolbox.com/epchan.

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## 37 comments:

(Leveraged) ETFs may also have excessive tracking errors. I have not done any systematic study, but briefly examined an ETF titled "ETFS 2X Daily Long WTI Crude Oil" (ticker 4RT6 in XETRA). In one year period from spring 2015 to spring 2016, the underlying non-leveraged index closed at roughly the same level, but the ETF shares (or NAV per share) lost about three quarters. Bloomberg currently puts 1yr return at -73.74%, taking into account a reverse split. Most of that loss cannot be explained by the fact that the ETF is supposed to replicate daily leveraged returns. Based on this, it is essential to have long-term data on how an ETF has performed against the (simulated) index, although some ETFs like physical gold funds (of reasonable size) can probably be safely assumed to track it quite faithfully. Of course, it is also important to remember the difference between daily and long-term returns, as pointed out in the post.

Hi Ernie,

What kind of price do you use to calculate P/E ratio in backtesting, adjusted or unadjusted?

Thanks.

Typically earnings per share was not adjusted, hence one must use unadjusted price as well.

Ernie

Hi Ernie,

Thank you for quick response.

But for stocks split, there would be big change in unadjusted price, so P/E ratio in backtesting. How do we deal with that?

Thanks.

If both earnings and prices are unadjusted, their ratio is invariant with respect to any splits or dividends.

Ernie

I should clarify that by "earnings", I meant "earnings per share".

Ernie

Hi Ernie,

However, it seems earnings per share just updates quarterly, but price updates every day.

There would be a gap window between them. Thanks.

Whenever there is a split, earnings per share will change in the same % as market value per share (i.e. market price). Earnings per share won't just update quarterly in this situation.

Ernie

Hi Ernie,

Can we get pre-open quotes for US stocks via IB data feed?

Thanks.

Sure we can!

Ernie

Hi Ernie,

Is that easy to buy mid-cap US stocks at open prices?

Thanks.

If you send in a Market On Open order, you are guaranteed to get filled at open price, unless you are buying millions of shares.

Ernie

Hi Ernie,

If we send in a Market On Close order, are we guaranteed to get filled at close price?

Thanks.

Yes, you are.

Ernie

Hi Ernie,

In your second book, you talk about interday momentum strategies, and you mention a "Time series momentum" paper written by Moskowitz, Yao, and Pedersen, 2012.

I find that in their paper, they use "excess return" to build the momentum strategy.

Do you know what is the definition of "excess return" in their paper?

Thanks.

Excess returns mean returns minus risk free rate.

Ernie

Hi Ernie,

Would you please recommend some papers about order book trading strategies?

Thanks.

Please see the book by Cartea et al. on Algorithm and High Frequency Trading on my Recommended Books list on the right sidebar.

Ernie

Hi Ernie,

Do you trade "join the bid" high-frequency strategy in your book for futures?

Thanks.

No, we haven't tried that yet.

Ernie

Hi Ernie,

Are all US bond futures pro-rata matching?

How do we know they are pro-rata matching?

Thanks.

To my knowledge, only Eurodollar futures has pro-rata matching on CME. You should watch the talk by Dr. Edith Mandel at QuantCon 2016. It was an amazing talk on trading the ED market.

Ernie

Hi Ernie,

Sounds great!

Where can we watch "Quantitative Trading in the Eurodollar Futures Market" by Edith Mandel?

Thanks

It would be best if you direct this question to QuantCon's organizer Quantopian.com.

Ernie

Hi Ernie,

If we send MOO in IB TWS, could we save bid-ask spread?

How does IB handle MOO?

Thanks.

Sure, MOO order is executed during the closing auction. Nobody pays bid-ask spread.

IB or any broker will just route it to the exchange for this auction. But note that you need to submit this order 10 minutes or more ahead of the close (based on NYSE or Nasdaq rules).

Ernie

QuantCon has given me these special links for our readers here:

"Quantitative Trading in Eurodollar Futures Market" by Edith Mandel:

Video https://vimeopro.com/user7561422/quantcon-2016-videos/video/164045995 (Enter password: WeLoveQuantsQ2016!)

Slide Presentation https://www.slideshare.net/secret/se7g2urie9h3xp

Enjoy!

Ernie

hi Ernie,

In Kalman filter, in the state equation, I find there are two kinds of version in references, they are

m(t) = m(t-1) + w(t-1), and

m(t) = m(t-1) + w(t),

I am confused here.

Do you know the difference between them?

Thanks.

w is a Gaussian noise term. There is no time series model for how it evolves, and you can consider it as serially uncorrelated. Hence it doesn't matter whether you use w(t) or w(t-1).

Ernie

Hi Ernie,

Thank you for quick response.

However, in m(t) = m(t-1) + w(t-1),

at time t, w(t-1) is realized, not random anymore, which is weird.

I prefer m(t) = m(t-1) + w(t), making more sense, time index of white noise should be consistent with that of dependent variable.

To comment on what Lauri said earlier, the discrepancies you witnessed between leveraged ETPs and their underlying indices really have 2 components: the first one is beta slippage, which is inevitable for products that only track day-to-day returns, even if the ETP tracks its underlying perfectly the slippage will still occur and it has a path-dependent quality. I believe Euan Sinclair talked about this in his book "Volatility Trading". The second component is the actual tracking error, this is very easy to model as you can simply compare the return of a perfectly tracking model of a index to the return of the actual ETP that has the same leverage. For highly volatile ETPs such as the JNUG & JDST pair, the tracking error alone can be more that 60% annually. There's also an observable linear relationship between the tracking errors of leveraged ETPs and the volatilities of their underlying indices. Low volatility pairs such as the SPXL and SPXS almost have no tracking error over a one year period.

Hi RayRay,

Great points!

Just for clarification: when you said "beta slippage", are you referring to the discrepancy between the long term (not daily) growth rate of levered ETP vs. the long-term growth rate of the unlevered ETP multiplied by the leverage?

Interesting observation that tracking error is linearly proportional to volatility. I imagine that is due to the transaction costs of frequent intraday rebalancing?

Ernie

Hi Ernie,

Thanks for your quick comment. Yes, and imo slippage is even more visible when you compare the performance of the leveraged ETP during any period when the underlying index's return is almost flat. But this quality is indeed path dependent, theoretically the "slippage" will turn into a compounding surplus when the security has consecutive movements in one direction (obviously not realistic over longer period of time).

I haven't looked into the reason but I suspect transaction costs is a big part of it.

Hi Ernie,

Thanks for the quick comment. Yes, and the discrepancy is more visible during any period when the underlyng's return is flat. I haven't look into the reason for the relationship but I suspect transaction costs are a big part of it.

Thank you very much for your insights, very glad I found this blog.

Ray

i'd love to attend one of your workshops. Where can I get more info please?

Luke from trading secrets

Hi Luke,

Thank you for your interest. Please visit epchan.com/workshops for details.

Ernie

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