Is all S&P 500 margin expansion coming from tech sectors?
Core argument: All of the increase in the S&P 500's operating margin over the past 20 years has come from tech-related sectors, defined as communication services, consumer discretionary and information technology.
Operating margin measures the share of revenue left after covering operating expenses such as wages, materials and overhead. The chart shows that over the past 20 years, all of the increase in the S&P 500’s operating margin has come from tech‑related sectors [Tech related includes communication services, consumer discretionary and information technology], while operating margins for non‑tech companies have stayed near 9%.

