An undivided account is an initial public offering (IPO) for which there are multiple underwriters. In a western account, each underwriter takes responsibility only for its own shares of the total that remain unsold. Naturally, there is a variation called an eastern account in which each underwriter takes responsibility for placing any shares that remain unsold.

That is, each firm agrees to pick up the slack if other underwriters fail to sell the portion of the total number of shares that they have been allocated.