The odds ratio is printed with a special format, just like the more-familiar p-values in SAS. When a p-value gets to small, it is printed as "<.0001". In the same way, when an odds ratio becomes too big, it is printed as ">999.999 ". The true value is in the table (use ODS output to save the table to a data set), but you are seeing the formatted value.
If yuo want to know why your odds ratio is so large, that is a modeling question that requires knowing more about your model and data.
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