yager....这有篇文章讲 skf 的，我刚看到，觉得挺有道理的，转来你看一下，
http://sovereignspeculator.com/2008/08/08/inverse-etfs-vs-leaps-puts/
Inverse ETFs are best used for trading, rather than to buy and hold
for the duration of a bear market. Non-traders looking to hedge their
longs or profit from the bear market should consider long-term put
options instead. Contrary to popular belief, options can require less
expertise and offer a lower overall risk to a portfolio than short ETFs.
Brutal math
The main problem with short ETFs is that as the underlying indexes
get lower, small dollar moves become large percentages, especially in
2X funds. This math works against you as the market exhibits volatility
on its way down. A dollar of loss in an index wins you a smaller gain
in your short fund than a dollar of gain in the index from that lower
level gives you a loss in your fund. Here’s an illustration:
Imagine if XLF (a financial index ETF) goes from 20 to 19 one day, and SKF (SKF’s 2X inverse) goes from 100 to 110.
$1 out of $20 is 5%, so SKF goes up 10%
$1 down = $10 up
The next day XLF goes from 19 to 20, so SKF goes to $98.42 . $1 out of $19 is 5.26%, so SKF goes down $11.58.
XLF is back where it started, but SKF is down 1.42%.
As many have learned in the bounce from the July 15 lows, this math
can be brutal with larger percentage swings, and these moves will only
get wilder as the market goes lower.
LEAPS are lower risk than short ETFs (in smaller quantities)
If you are very confident about financials or REITs or the broad market going lower and are not a proven trader, use LEAPS (Long Term Equity Anticipation Securities),
long-dated options. The whole idea behind the existence of an options
market is to decrease risk. Make the concept work for you.
You can buy January 2010 puts on XLF, IYR, SPY, IWM, QQQQ, whatever
you want, and just sit tight. 2011 LEAPs are being rolled out, and
December 2010s are available on SPY. Don’t trade in and out if you
aren’t a pro. Those blistering rallies on the way down won’t change the fantastic percentage gains that await if you have the longer trend right.
more on line..
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狗仔卡
发表于 2008-9-20 12:04 PM
