Banks, reluctant to reveal much corporate strategy, say little. Old Kent Financial Corp., which seeks to double its authorized shares to 300 million from 150 million, says the move is housekeeping. The bank did a 2-for-1 stock split on Dec. 15 and says its present pool of stock would be too small for a similar split in the future, "although the board of directors has no present plans or expectations as to if and when further splits would be decided." In the market Tuesday, shares of Chase Manhattan Corp. rose $3.125 to $124.6875, after Goldman, Sachs & Co. upgraded the stock. The upgrade was intriguing because Chase is rumored to be interested in acquiring Goldman, one of Wall Street's last private partnerships. Goldman, however, does not seem to be interested in selling.