Method and apparatus for enabling smaller investors or others to create and manage a portfolio of securities or other assets or liabilities on a cost effective basis

A computer-implemented method for managing a plurality of investment accounts owned by a plurality of investors, each account being associated with a third party user, comprising:

• receiving data from the user via a computer network regarding the plurality of investment accounts, the data defining the amount and types of investments to be included in each investment account;
• aggregating with a computer the plurality of investment accounts into a single portfolio of investments for the user;
• establishing with the computer an aggregate portfolio of investments from the third party user and from a plurality of other users, wherein said establishing an aggregate portfolio includes combining orders for investments from the third party user and from the plurality of other users into a single order for each investment, including combining at least one order including a fractional share, a single share or an odd lot of shares for an investment;
• and
• analyzing with the computer the single portfolio to determine a risk/reward characteristic of the single portfolio;
• wherein the investments in each account are owned directly by the investor that owns the account.