To be honest I'm a little confused. I think you said that these estimates are for a two week time horizon, right? The time horizons we have right now for the allocation program are three week. So essentially are expected returns are a little higher and are STD's are a little higher in our current estimates for our holdings than they would be for a two week time horizon. We could just cut these estimates by a 1/3rd if we wanted to. Hopefully someone will weigh in on this.
In terms of calculating or estimating STD numbers:
You can do STD a number of ways but maybe the easiest is going to ishares and scrolling to the bottom of the page. They list the some details about the ETF's like its beta value and STD. I'm pretty sure this is 52 week data (iShares is down right now so I can't look for myself to confirm) so it would have to be adjusted for our 2 week time horizon. Keep in mind there is a square root in the calculation of STD so a linear decomposition of that STD won't be accurate (i.e. dividing that number by 52 won't necessarily give us a good estimate of STD for 1 week). Instead maybe just comparing relative to the IVV is a better technique. So I know the IVV has a STD around 18 or 19% so if IAU is somewhere like 23% than whatever STD we expect for the IVV is probably going to be lower than for IAU.
This is why I think it is important to evaluate the IVV and base our numbers partly off the IVV. If we have good estimates for the IVV than we can get good estimates for everything else. So if we expect the IVV to have a STD of 2% over the next two weeks, than we can guess that the IAU will have a slightly higher STD maybe 2.1-2.5%. And if GSC has a 52 week STD of 28% than over a 2 week time horizon, if we guess the IVV will have a STD of 2%, then GSC is more likely to be in the 2.3-2.7% range over the next two weeks due to its comparatively higher 52 week STD.
Keep in mind these are baseline numbers. So a good starting point for IAU maybe in the 2.1-2.5% range but then we take into account the economic factors over the next two weeks that might push it higher or lower or keep it in the middle.
This is just one method to try and determine STD numbers but this is already pretty long so that's probably enough for now. Luckily the markets are closed today so we have plenty of time to get these estimates.
I should be around my comptuer most of the day so I'll be able to respond, hopefully promptly, to any questions or comments about this email.
Phil