The Pattern Hiding in Your Portfolio
Pull up your brokerage app and look at what you bought in the last twelve months. There’s a good chance it’s whatever had the best headline return the year before — a hot sector fund, the stock everyone was talking about, the ETF that doubled while the rest of the market crawled. That’s recency bias: the tendency to treat the most recent data as the most predictive, even when history says otherwise.
Why Your Brain Does This
Recency bias isn’t a character flaw, it’s a shortcut your brain uses everywhere. Vivid, recent information is easier to recall than a chart of 20-year average returns, so it feels more “true.” Fund companies know this too, which is why last year’s top performer gets the flashy ad and the cash inflows — right as that fund’s run is often ending. Morningstar has tracked this repeatedly: funds that top the performance charts one year tend to underperform their category average in the next three to five, because outperformance is frequently a sector or style getting its turn, not a repeatable skill.
The Cost of Chasing Performance
This is how investors end up with a timing problem even when their fund choices are fine. The math is called the “behavior gap” — the difference between a fund’s published return and the return its actual investors earned, because investors piled in after the run-up and sold during the inevitable dip. Studies from firms like Dalbar have put that gap at several percentage points a year, compounded over decades. It’s rarely one bad decision; it’s a pattern of buying high on excitement and selling low on fear, repeated every market cycle.
A Simple Fix That Actually Works
You don’t need to predict markets to break this habit — you need a rule that removes the decision in the moment. Three that work well together: first, set your asset allocation (the split between stocks, bonds, and cash) once, based on your timeline and risk tolerance, not on what’s been hot lately. Second, rebalance on a schedule — quarterly or annually — rather than when a fund “feels” overdue for a correction; rebalancing mechanically forces you to trim winners and add to laggards, which is the opposite of recency bias. Third, before buying anything because of its recent performance, ask “would I buy this if the chart only showed the five years before last year?” If the answer changes, that’s the bias talking, not the fundamentals. A portfolio built on a plan beats a portfolio built on a highlight reel almost every time.
