E-Trade, Goldman Each Buy 25% of ECN

E-Trade Group Inc., the No. 2 online brokerage, and Wall Street giant Goldman Sachs Group each agreed to acquire about 25% of the Archipelago electronic network for trading Nasdaq stocks. Archipelago is one of nine ECNs, or electronic communications networks, approved by the Securities and Exchange Commission to use computers to match purchase and sale orders outside the stock markets’ trading systems, anonymously and without intermediaries. Palo Alto-based E-Trade and New York-based Goldman will buy their stakes from founding partners Virago Enterprises and Townsend Analytics Ltd. The four groups will each own about a quarter of a new company, Archipelago Holdings, said E-Trade, which paid $25 million for its stake. Separately, E-Trade and UAL Corp.’s United Airlines, the world’s biggest airline, will offer 25 million United customers more than 1,000 frequent-flier miles if they open an E-Trade account. E-Trade will pay the Chicago-based airline for free miles awarded to customers in United’s Mileage Plus program. Last month, E-Trade and closely held Netcentives Inc., an Internet promotions company, began offering new E-Trade brokerage customers 5,000 air miles on six major airlines, including United, through the https://www.clickrewards.com Web site. E-Trade shares rose $9.75, or about 18%, to a record $64.06 on Nasdaq.