Strange result on to.Monthly (quantmod package) cut series

Question

Problem with my to.monthly. He cuts my data series, I don’t know why.

####install.packages("quantmod")
library(quantmod)
####install.packages("PerformanceAnalytics")
library(PerformanceAnalytics)
####install.packages("zoo")
library(zoo)

####Definindo diretório principal
setDefaults(getSymbols, src='google')

StartDate = as.Date("2004-01-01") ####data de começo
EndDate = as.Date("2017-01-01") ####data de término


ibovespa <- getSymbols('IBOV', from=StartDate, to=EndDate, auto.assign = F)
ibovespa_monthly <- to.monthly(ibovespa) #->->->->->->->->->problem#####
colnames(ibovespa_monthly) <- c("Open", "High", "Low", "Close","Volume")
ibovespa_return <- (Return.calculate(ibovespa_monthly$Close)[-1,])*100
plot.zoo(ibovespa_return, xlab="Mês", ylab = "Porcentagem")

table.CalendarReturns(ibovespa_return)

Answer 1

Note that from 2013-06-27, the column ibovespa$IBOV.Volume has only NA. The function to.monthly cannot, as far as I know, deal with this lack of information.

Note that if I switch assets, this error ceases to occur:

petr4         <- getSymbols('petr4', from=StartDate, to=EndDate, auto.assign = F)
petr4_monthly <- to.monthly(petr4)
petr4_monthly

I know little about the stock market, but I don’t think it makes sense to record the volume of the Bovespa index as a whole. It makes sense to think of the volume of negotiations of a particular role, whether VALE5, ITUB4 or PETR4, as in the example. But of Bovespa as a whole I think it makes no sense. I, at least, have never seen.

Therefore, what I suggest is to remove column 5 from the object bovespa for the other results to be calculated correctly.

ibovespa         <- getSymbols('IBOV', from=StartDate, to=EndDate, auto.assign = F)
ibovespa         <- ibovespa[, -5]
ibovespa_monthly <- to.monthly(ibovespa)