Own-account software (OAS) investment is the investment in software assets in-house for use within the firm: an increasingly important form of intangible investment. I consider methodological developments for UK estimates of OAS investment. First, I estimate OAS investment using the quarterly Labour Force Survey (LFS), following the method used by the Office for National Statistics (ONS) almost exactly, which uses the Annual Survey of Hours and Earnings as its main data source. This produces the first genuinely quarterly estimates of OAS investment, which enable a better understanding of recent trends in the economy than existing estimates. These quarterly estimates suggest considerably stronger growth during 2020 and 2021 than in official estimates, with implications for other National Accounts variables. In constructing these figures, I also develop time factors for Standard Occupation Classification (SOC) 2020 codes for the first time. Second, I consider other improvements in measurement, including an approach that combines ASHE and LFS data, improved calculation of sales adjustment factors, and treatment of the self-employed.