troubleshoot stock() call error

BAstock.R

# BA.csv
 
Date,Open,High,Low,Close
2013-12-31,136.16,137.05,135.74,136.49
2013-12-30,137.16,137.37,135.54,135.92
2013-12-27,138.69,138.88,136.79,136.9
2013-12-26,137.18,138.59,137.17,138.27
2013-12-24,136.4,136.98,136.14,136.83
2013-12-23,137.69,138.09,136.32,136.4
2013-12-20,135.49,137.85,135.49,136.67
2013-12-19,135.0,136.23,133.94,135.17
2013-12-18,135.86,136.44,132.84,135.49
2013-12-17,137.92,138.1,135.36,135.88

sym <- as.xts(read.zoo('BA.csv', header=TRUE, sep=','))
indexClass(sym) <- "POSIXct"

stock(sym, currency='USD')

# Error: evaluation nested too deeply: infinite recursion / options(expressions=)?