Example 13 - Reading 16

[broadex]

Real stock price indext = Nominal stock price indext × CPI2009 ÷ CPIt
Real earningst = Nominal earningst × CPI2009 ÷CPIt+1
Why use t+1 for real earnings?? This is probably level I material but im stuck!

 

[FrankCFA]

CPIt+1 = Nominal earningst/Real earningst× CPIt

 

[Audacious]

This would be the case if the Index value is from the beginning of the year; while earnings are from the end of the year (of course). So the CPI of earnings is almost one year after the CPI of the index.
I think