Shares in Tulip Computers NV fell nearly 12% at the opening yesterday after the Den Bosch, Netherlands personal computer manufacturer warned that it expected to report a loss for the first half after revaluing stock to take account of plunging chip prices. Tulip stressed that it expected a profit in the second half, but added that it was still unclear if it was able to close the full year 1996 with a positive result. Revenue has increased by 17%, which is in line with expectations; month-end inventories will be down 20% on a year ago. Tulip also reiterated that it was in preliminary negotiations about a strategic co-operation with an unidentified company, but said the outcome was unclear.