Just to be clear there is no underlying INDEX. As you said it tries to replicate owning the first two months of the curve based on time to expiration and resets daily moving from front to back month until front month expires and it starts all over again. It does not track any index. If the VX futures in the front month fall 3%, VXX does not fall 3%. It could fall more or less than that depending on the % of the components. If VIX spikes 10%, VXX could move 20% or could move 3%. This is NOT, NOT a tracking ETF.
Your ETNs Are Not Linked to the VIX Index: The value of your ETNs will be linked to the value of the underlying index, and your ability to benefit from any rise or fall in the level of the VIX Index is limited. The index underlying your ETNs is based upon holding a rolling long position in futures on the VIX Index. These futures will not necessarily track the performance of the VIX Index. Your ETNs may not benefit from increases in the level of the VIX Index because such increases will not necessarily cause the level of VIX Index futures to rise. Accordingly, a hypothetical investment that was linked directly to the VIX Index could generate a higher return than your investment in the ETNs.
One series of ETNs that is linked to the performance of the S&P 500 VIX ShortTerm Futures™ Index TR that is calculated based on the strategy of continuously owning a rolling portfolio of one-month and two-month VIX futures to target a constant weighted average futures maturity of 1 month; (NOT LINKED TO AN INDEX, it is tracking a portfolio)
Your ETN Is Not Linked to the VIX Index and the Value of Your ETN May Be Less Than It Would Have Been Had Your ETN Been Linked to the VIX Index
Index Components(as of 07/21/2016)
Index Components
Weightings %
CBOE VIX Future AUG 16 88.90%
CBOE VIX Future SEP 16 11.10%
If we choose not to issue additional ETNs or to cease or suspend sales of the ETNs from inventory, this will impact supply and demand for the ETNs and may impact the liquidity and price of the ETNs in the secondary market.
let us not forget this little gem:
* 2,500,000 ETNs, principal amount $100 each, were issued on February 3, 2009, an additional 2,500,000 ETNs, principal amount $100 each, were issued on July 2, 2009; an additional 10,000,000 ETNs, principal amount $100 each, were issued on July 24, 2009; an additional 10,000,000 ETNs, principal amount $100 each, were issued on November 5, 2009; an additional 10,000,000 ETNs, principal amount $100 each, were issued on January 7, 2010; an additional 15,000,000 ETNs, principal amount $100 each were issued on January 22, 2010, an additional 25,000,000 ETNs, principal amount $100 each were issued on March 16, 2010; an additional 5,000,000 ETNs, principal amount $100 each were issued on May 3, 2010; an additional 20,000,000 ETNs, principal amount $100 each were issued on August 13, 2010; an additional 20,000,000 ETNs, principal amount $100 each were issued on September 7, 2010; an additional 25,000,000 ETNs, principal amount $100 each were issued on September 21, 2010 an additional 15,000,000 ETNs, principal amount $100 each were issued on October 20, 2010 and an additional 10,000,000 ETNs, principal amount $100 each were issued on October 28, 2010. On October 26, 2010, Barclays Bank PLC announced a 1 for 4 reverse split of the ETNs, effective November 9, 2010. Following the reverse split, 42,500,000 ETNs, principal amount $400 each, were outstanding. An additional 7,500,000 ETNs, principal amount $400 each, were issued on January 11, 2011, an additional 20,000,000 ETNs, principal amount $400 each, were issued on March 14, 2011, an additional 15,000,000 ETNs, principal amount $400 each, were issued on March 5, 2012, an additional 15,000,000 ETNs, principal amount $400 each, were issued on March 16, 2012; an additional 50,000,000 ETNs, principal amount $400 each, were issued on March 19, 2012; an additional 25,000,000 ETNs, principal amount $400 each, were issued on August 17, 2012 and an additional 25,0000,000 ETNs, principal amount $400.00 each, were issued on August 24, 2012. On September 21, 2012, Barclays Bank PLC announced a further 1 for 4 reverse split of the ETNs, effective October 5, 2012. Following the reverse split, 50,000,000 ETNs, principal amount $1,600 each, were outstanding. An additional 10,000,000 ETNs, principal amount $1,600 each, were issued on October 12, 2012, an additional 10,000,000 ETNs, principal amount $1,600 each were issued on February 21, 2013, an additional 20,000,000 ETNs, principal amount $1,600 each were issued on March 25, 2013, an additional 20,000,000 ETNs, principal amount $1,600 each were issued on July 30, 2013, and an additional 40,000,000 ETNs, principal amount $1,600 each were issued on August 8, 2013. On October 25, 2013, Barclays Bank PLC announced a further 1 for 4 reverse split of the ETNs, effective November 8, 2013. Following the reverse split, 37,500,000 ETNs, principal amount $6,400 each were outstanding. An additional 12,500,000 ETNs, principal amount $6,400 each were issued on May 27, 2014, an additional 20,000,000 ETNs, principal amount $6,400 each were issued on March 18, 2015, an additional 20,000,000 ETNs, principal amount $6,400 each were issued on June 8, 2015, an additional 60,000,000 ETNs, principal amount $6,400 each were issued on April 26, 2016 and an additional 50,000,000 ETNs, principal amount $6,400 each were issued on July 22, 2016.
After the splits the higher value allows the fund to issue even more ETNs to increase number of "shares" So after reverse split they reflood the market with more ETNs to bring in more capital to the account and the decay is on a much larger pool of money.
This is all in the prospectus is you want to read about it.