Split n then concatenate files.

I have a file which has 350,000 records.
I want all of these in 1 excel sheet file(around 6 worksheets)
I used the below command to split it.

split -64000 Creditratingsdata.xls credits

Now i am having problems of appending into 1 excel file.
I even went to the extent of trying.

(cat (split -64000 Creditratingsdata.xls credits) >> why.xls)

so that the split file will be appended into why.xls........

ANY IDEAS ONTHE SAME LINES..............!!!!!!!!

What are the files split created .And if you are concatenating several files use '>' instead of '>>'

what about ....

rm credits*              # not removing Creditratingsdata.xls
split -64000 Creditratingsdata.xls credits
cat credits* > x.xls

I tried the below given by u...

cp Creditratings.txt Creditratingsdata.xls
split -64000 Creditratingsdata.xls credits
cat credits* > x.xls

But it doesn add a new worksheet.
only one worksheet is created and
rows from 64001 get filled in that worksheet till 65536.
The remaining data is not loaded.

Hi thumsup 9.
the files created are......
creditsaa
creditsab
creditsac
creditsad