For the purpose of letting the funds the board shall divide the funds into not less than two nor more than ten equal parts. Each bidder may bid for any number of the parts, but the bid for each part shall be separate. Any banking institution in the county or in an adjoining county desiring to bid shall deliver to the secretary of the board, on or before the date selected for the acceptance of bids, a sealed bid, stating the rate of interest, or method by which the interest will be determined, that the banking institution offers to pay on one part of the funds and moneys of the school district for the term of one to five years, as the case may be, next ensuing the date of the bid; or if the selection is made for a less term as provided in sections 165.201 to 165.291, then for the time between the date of the bid and the next regular time for the selection of depositaries, as fixed by section 165.211. It is a misdemeanor for the secretary of the board to directly or indirectly disclose the amount of any bid before all bids are opened at a public depositary bid opening.