I have a table that carries data with cumulative return of some instrument. Data is described with start date, end date and cumulative return for date range (start-end):
Start Date|End Date |Cumulative Return 06/23/2013|03/17/2015|0.358702433 07/07/2013|03/17/2015|0.38655325
But now, I need to calculate cumulative returns for other date ranges, for instance a cumulative return between 06/23/2013 and 07/07/2013 . Is is possible to do it with some generic formula?