Long term correspondence betwen TSP funds and live chart symbols

[snoopyd]

Hi guys. For years I have always looked at the live chart symbols (^DWCPF, EFA, etc..) that were said to be approximately similar to the TSP funds and never doubted them. But I was just doing some analysis using some reference points over a large timeframe (e.g 2/25/20 vs last Friday) on EFA vs I fund. The numbers came out to be:

on 2/25/20 I Fund @ 30.43 and EFA @ 64.45
on 9/23/22 I Fund @ 29.11 and EFA @ 56.76

for I Fund: (29.11 - 30.43) / 30.43 = -4.3%
for EFA: (56.76 - 64.45) / 64.45 = -11.93%

I'm not sure if I misunderstand something. I didn't look at the F, C and S, but just on the I fund as an example, the % difference is quite large between EFA and I fund over roughly 2.5 years. Could it be that we should only use the EFA to estimate the I fund for a short term but don't rely on them at all for the long term?

[mjedlin66]

EFA is considerably different than the I fund. The chief difference is the pseudo magic known as "fair valuation", which is performed by Blackrock after close each day. It considers currency fluctuations and also current events. I don't know of any way of modeling it.

It is maddening. But until the TSP posts their daily I fund prices each day, the EFA is the closest bet.

Long term, absolutely use the I fund share prices instead of EFA.

[12squared]

You also need to consider that dividends get rolled into the price. This is true for all the funds.

[snoopyd]

Thanks for the insights, mjedlin66 and 12squared!