dateFrom String returns incorrect date

dateFrom String returns incorrect date

I have been struggling to figure out why dateFromString method returns
wrong date. Here is the code.
NSDate *secondDate = [df dateFromString:@"12.31.9999"];
and the out put for it is as below.
1999-12-31 07:00:00 +0000
Please need help. Is it the problem with the method?? The same works fine
in iOS5. The issues is only in iOS6.
Thanks