In theory, anyone can be a Warren Buffett. The most modest retail investor may search out value, then buy, hold and slowly accumulate. What they cannot do is be a Goldman Sachs. The idea that bedroom day-traders might ever compete equally with professionals is a fiction convenient to the retail broking industry.

That fiction is now hitting reality. Senator Ted Kaufman is upset that hedge funds use super-fast trading and computer algorithms to buy and sell shares, and wants the Securities and Exchange Commission to review market structures to make everything fairer. Goldman Sachs is also under fire for reports that it does not share the short-term views of its analysts equally with all its customers. Yet neither activity should greatly exercise regulators.