did your father have a will or trust agreement that specified the splitting of that asset or are you doing it to be fair to your sibling?
there are no incme tax consequences.
unless there is a requirement to split the account you are making a gift for the amount sent to your sibling. since it is over $16,000 a gift tax return is required. it is unlikely that any gift tax but you will use up a portion of your lifetime exemption which is currently over $12million
