Halliburton Co has signed a letter of intent to acquire a 60% stake in Texas Instruments Inc’s Geophysical Service Inc seismographic services unit in Dallas for $50m plus performance-related payments to be made in 1991. Halliburton also gets an option to buy the 40% minority, again at a price that will be tied to performance. Texas Instruments is seeking to shed its non-electronics businesses, and has reduced operating costs at the loss-making unit by $100m over the past year to prepare it for sale. Geophysical Service Inc made a $77m pre-tax loss in 1986 and expects to report a much smaller loss for the year just coming to an end.