Hello,
This thread is quite helpful for benchmarking tests for Heston models thanks !
I have a similar concern but for forward start options : is there a paper or source that provides Forward start options prices under Heston that have been computed to high precision for a range of strikes
High precision (more than a couple of decimals) results for forward starting options in Heston do seem elusive, I couldn't find any (but maybe I didn't look enough). They are apparently no more difficult to value than vanillas (fast, via the forward characteristic function, for those familiar with such methods, not me), but all the papers I've seen do not offer any calculated values for reference. So I thought I'd give it a go in a stupid, brute force kind of way, initializing my PDE pricer with forward-starting vanilla values calculated with a dll I found (fast closed-form from
http://www.axelvogt.de/axalom). If this dll isn't good enough for 10 digits, then my last digit(s) would be off. (there are two versions, I used the "exact" one). So here you go:
Call, forward starting at t1 when the strike is set as
k*S(t1). t1 = 1Y, T = 2Y. S0 = 100;
Heston parameters: spot var = 0.010201, long-run var = 0.019, reversion rate = 6.21, vol of vol = 0.61, rho = -0.7. r = 0.0319
k = 0.5, FSCV = 51.57684084
k = 0.75 FSCV = 27.62484139
k = 1 FSCV = 6.95391850
k = 1.25 FSCV = 0.126962361
k = 1.5 FSCV = 0.0005246392
This being quite makeshift I cannot guarantee the above values 100%, but if someone matches them then we're both happy.
Obviously this is not the recommended way to price those, but it's a way to provide some reference values, certainly more accurate than what MC could manage.
But what if this was American and/or paid discrete dividends? How would you price it? I'm guessing augmented PDE or LS MC.