Management at NBI Inc, Boulder, Colorado is spreading itself too thin, and as a result, the company’s various businesses are underperforming, a Woodside, California investment group believes. The group, Fisher Investments Inc, has held about 4% of the company’s shares for some time, and has now taken its stake to 5.17% by making additional purchases this month and last. NBI started life as a dedicated shared logic word processing systems business, but in 1984 started diversifying by buying a couple of small Unix systems businesses and a string of office products and supplies companies. Fisher believes there is no synergy between the computer and office products sides of the company, and that one or other should be sold, so that management can devote all its efforts to the surviving business. Alternatively it suggests that the entire company should be liqui dated and proceeds distributed to shareholders, or one of the busin esses spun off to shareholders as a stand-alone company. Fisher says it will raise its stake subject to market conditions, and seek other like-minded shareholders to join it in putting pressure on NBI. NBI says it will review the proposals. Its shares jumped $1.125 to $5.25 Friday after the Fisher statement.