Price Versus Expectations Filter
Judge new information against expectations, not its headline direction
- Difficulty
- Easy
- Time to result
- ~days to results
- Steps
- 5
- Confidence
- 96%
The filter separates the emotional meaning of a headline from its economic meaning for a security. Begin by asking what outcome investors had already embedded in the price. Then compare the new result with that expectation: good news below expectations can drive prices down, while bad news above expectations can drive them up. Because markets incorporate public information rapidly, the next observable price usually reflects the surprise before an ordinary investor can trade. The practical output is therefore not a directional forecast but a decision rule: unless the information changes the investor's underlying goals, constraints, or planned allocation, do not trade merely because a headline sounds positive or negative.
Origin
Extracted from Masters in Business, where Larry Swedroe used contrasting earnings announcements to explain why headline direction does not determine market direction.
Core principles
- 01Prices already reflect widely known information.
- 02Market reactions depend on surprises relative to expectations.
- 03A positive headline can produce a negative return.
- 04Public information loses its trading value almost immediately.
- 05A durable investment plan matters more than rapid reactions.
How to run it
- 1
Separate the headline from the signal
Classify the announcement without treating words such as good, bad, growth, or decline as an automatic trading instruction.
Pro tip Write down the headline interpretation before looking at the price response so you can notice your initial bias.
Watch out A strong absolute result can still disappoint investors.
- 2
Estimate embedded expectations
Determine what analysts, traders, and the existing valuation appeared to anticipate before the release.
Pro tip Use consensus estimates or pre-announcement guidance when they are available.
Watch out Your personal expectation is not necessarily the market's expectation.
- 3
Measure the surprise
Compare the actual result with the embedded expectation and identify whether the surprise was positive, negative, or negligible.
Pro tip Focus on the gap between expectation and reality rather than the absolute number.
Watch out Do not infer the surprise solely from the wording of a press release.
- 4
Recognize the price adjustment
Assume that widely available information has been processed rapidly once trading begins.
Pro tip Treat an immediate price move as evidence that the market has already repriced the news.
Watch out Chasing the move can convert an informational reaction into a poorly timed trade.
- 5
Apply the plan test
Act only if the development changes your goals, risk constraints, required allocation, or another rule in your investment policy.
Pro tip Use a written investment policy to distinguish planned action from emotional reaction.
Watch out Newsworthiness alone is not a valid reason to alter a long-term portfolio.
In the wild
A company trading near sixty reports that earnings increased by one hundred percent. An investor sees the growth rate and assumes the shares must rise, but the next trade is near forty because the market had expected an even stronger result. The framework identifies the negative expectation gap before treating the headline as a buying signal.
→ The investor avoids chasing apparently good news that the market regards as disappointing.
General Motors announces that earnings fell twenty percent. The absolute result appears poor, but the shares rise because investors had anticipated an even worse decline. Comparing the result with expectations explains the move without requiring the investor to trade it.
→ The investor understands why negative news can coincide with a positive price reaction.
Common mistakes
Trading the adjective
Investors act because a result sounds good or bad without comparing it with the outcome already priced into the security.
Chasing an completed adjustment
Investors trade after the public announcement even though the first available price has already incorporated most of the information.
Confusing explanation with opportunity
Understanding why a price moved does not mean the move remains exploitable after it has occurred.
Is it for you?
Best for
It is best for long-term investors tempted to trade around earnings, economic data, analyst calls, or corporate announcements.
Not ideal for
It is not designed for specialized traders with tested infrastructure, proprietary information, and an independently validated short-horizon edge.
From the transcript
“All that matters if it's better or worse than the market already expected.”
“the market knows everything you know, and the minute news comes out, the market instantly adjusts to that new information”
“Research has sewn something like ninety five percent of the move occurs literally in the first price”
From the episode
At the Money: Lose the Noise