MPs for Sale? Returns to Office in Postwar British Politics

Many recent studies show that firms profit from connections to influential politicians, but less is known about how much politicians financially benefit from wielding political influence. We estimate the returns to serving in Parliament, using original data on the estates of recently deceased British politicians. Applying both matching and a regression discontinuity design to compare Members of Parliament (MPs) with parliamentary candidates who narrowly lost, we find that serving in office almost doubled the wealth of Conservative MPs, but had no discernible financial benefits for Labour MPs. Conservative MPs profited from office largely through lucrative outside employment they acquired as a result of their political positions; we show that gaining a seat in Parliament more than tripled the probability that a Conservative politician would later serve as a director of a publicly traded firm-enough to account for a sizable portion of the wealth differential. We suggest that Labour MPs did not profit from office largely because trade unions collectively exerted sufficient control over the party and its MPs to prevent members from selling their services to other clients.