Home
Authors
Tags
App
Get QuoteDark Inspirational Quotes App
" There are challenges in terms of the measurement of VAR for what are known as nonlinear derivatives, where things like gamma and vega are important dimensions of the risk. "
John Hull
Challenges
Important
Measurement
Related Quotes:
" The real challenge was to model all the interest rates simultaneously, so you could value something that depended not only on the three-month interest rate, but on other interest rates as well. "
John Hull
Well
Value
Only
" Yes, our tree has an interesting shape. The center branches reflect the shape of the zero curve. When extreme parts of the tree are reached the branching pattern changes to accommodate the mean reversion. "
John Hull
Changes
Mean
Tree
" One important measurement issue concerns the fat tails problem that I mentioned earlier. VAR is concerned with extreme outcomes. If the tails of the probability distributions we are using are too thin, our VAR measures are likely to be too low. "
John Hull
Problem
Measurement
Important
" Alan White and I spent the next two or three years working together on this. We developed what is known a stochastic volatility model. This is a model where the volatility as well as the underlying asset price moves around in an unpredictable way. "
John Hull
Three
Together
White
" We concluded that you cannot rely on delta hedging alone. It sounds simplistic to say that now, but back then, this was the sort of thing people were only just beginning to realize. "
John Hull
People
You
Say
" The problem with interest rates are that you are not modeling a single number, you are modeling a whole term structure, so it is a sort of different type of problem. "
John Hull
Problem
Modeling
You
" I guess any simple idea that is really good will catch on quickly. "
John Hull
Good
Idea
Really
" Our starting point then was trying to find a way to incorporate mean reversion into the HoLee model. "
John Hull
Starting
Trying
Way
" Briefly speaking, our conclusion is that stochastic volatility does not make a huge difference as far as the pricing is concerned if you get the average volatility right. It makes a big difference as far as hedging is concerned. "
John Hull
Average
Difference
Right
" Our research led on to other things, such as the fact that exchange rates are not lognormally distributed. "
John Hull
Fact
Other
Exchange
" The HoLee model was the first term structure model. I remember reading their paper soon after it was published and as it was fairly different from many of the other papers that I had read, I had to read it quite a few times. I realized that it was a really important paper. "
John Hull
Important
Remember
Reading
" When interest rates are high you want the average direction in which interest rates are moving to be downward; when interest rates are low you want the average direction to be upward. "
John Hull
Moving
You
Direction
" If each of your time steps is one week long, you are not modeling the stock price terribly well over a one-week time period, because you are saying that there are only two possible outcomes. "
John Hull
Time
Long
Modeling
" Our tree is actually a tree of the short-term interest rate. The average direction in which the short-term interest rate moves depends on the level of the rate. When the rate is very high, that direction is downward; when the rate is very low, it is upward. "
John Hull
Tree
High
Average
" I didn't become interested in derivatives until 1982, 1983. "
John Hull
Derivatives
Become
Interested
" We started giving presentations at practitioner conferences in 1986, and since then all of our derivatives research has been stimulated by contact with practitioners. "
John Hull
Giving
Started
Research
" I think VAR is a very healthy development within the industry. "
John Hull
Healthy
Within
Think