Behavioral finance FAQ / Glossary (Time)
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Dates of related message(s) in the
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Year/month, d: developed / discussed, i: incidental
Time arbitrage, time value
Time is money, OK, but people weigh time and money differently.
Is the time spent worth the money gained or saved?
Time can be enjoyed, time can also bring pain.
It can be strange to consider it as a ware that obey economic criteria.
But its relation with economics is that time makes you also a breadwinner ("time is money").
=> It has to be managed wisely when this aspect is at stake.
In that respect, studies have shown that people often have no clear idea
of what their time is worth.
When they are doing an arbitrage between:
The time they will need to spend in order
to gain or save some money,
The amount of money actually gained
people often rely on quick and easy rules of thumb
(heuristics) without collecting and fully analyzing all
Do people spend enough time spent to think about
...what time to spend?
In order to make decisions, people often take less thinking time:
about time saving or time spending
than about money saving or money spending.
(Investment) Time horizon, bias, preference, span
.03/4d - 05/10i,12d - 08/3d
+ long shot bias, (narrow) framing,
overtrading, short time bias,
calendar effect, active / passive
- Time is money, OK, but people use different clocks.
In finance, time is a crucial ingredient. For money to give incomes is a matter of time.
Rates of return use a time criterion as their denominator (yearly rate usually).
The time horizon is the delay foreseen for an economic goal to be fully reached.
The time preference is the preference between operations giving short term or
long term results
Every economic player has a time criterion,
which can vary from an operation to another.
This personal time horizon / time preference is one of the factors
(together with return and risk) that drives its choice between projects.
For managers, the time horizon is a crucial factor when planning an action.
1) Short term / long term as investment criteria
Cutting investor time into salami slices
An investment time horizon is the delay foreseen to get an expected return on the
As there is, as seen below, some human appreciation on time horizons;
what is considered ST, MT and LT might vary with people and situations.
Let us say that, in financial and economic matters, it is rather commonly
Very short term is a few hours, a few days, maybe a few weeks
Short term is some months, until one year, or maybe two years,
Medium term includes various slices of time neither
too short or long (3 to 7 years generally).
Long term is above 7 years, maybe until 20
Very long term is over 20 years.
Types of investment operations, as well as investor styles, are largely related to
the time horizon.
Usually, money and financial markets, financial institutions, and of course
investors, make a distinction between:
Long term (LT) operations. This is what is behind the word "investing".
Above all, it applies to stable investing, with rare arbitrages (sometimes
called "passive management") or "buy and hold".
Short term (ST) operations.
Here are two categories of ST operations which are quite opposite
in their process and motivation:
Temporary savings (savings deposit, monetary fund...)
Trading, which is the frequent buying and selling of assets,
something also called "active management" (see active).
An investor's time horizon / time span is his preference (due for example
to its situation or its risk attitude) between:
Either short term rewards or safety. Here, two main examples:
The wish to "make money fast" whatever the
On the contrary the prudent goal to keep and manage safely some
liquidities that the player might need soon.
Or long term rewards or safety.
For example the will to save money
for the old age , or for a remote project,
Or just a general and deep-seated mental aptitude and liking for
anticipating things in the long run
(yes, the long term bias exist also, as explained below).
2) Factors that make an investor's time horizon / span
Everyone its own timepiece.
The time horizon or preference can be:
Rational, as related to life goals and life situations
(obviously, how old is an investor has an impact on his time preference).
Or emotional (impatience...).
Emotions (and also automaticity / habits) can be more active in short term decisions
while long term ones might be more rational
Or a cognitive expectation, either realistic or biased.
What can make it biased are either short-sighted considerations,
or on the contrary a long term illusion.
They can distort decisions (ST bias or LT bias).
If those biases are widespread among financial players, market
pricing anomalies can ensue.
The time preference is not so clear-cut.
An investor can follow several goals that imply different time horizons and
This should be done quite consciously (see below "time diversification"),
if not it could lead to contradictions: see "mental compartments".
3) Time horizon biases: what about the ST bias?
Time myopia? Impatience?
The best known (and most common) time horizon bias is the short term bias .
One of its causes is a mental myopia. It focuses on the immediate future and fast results,
with a disinterest for the longer view. This is sometimes called "narrow framing" (see framing).
Other factors intervene also, such as a lack of self-discipline.
Here are some aspects:
Many people would not spare enough voluntarily for their old days. This is:
either because they don't see the need.
This would be just a cognitive bias (time myopia),
or more probably (and emotionally) because they lack the self-discipline and
willpower (*) to resist immediate gratification such as consumption.
This is the reason why putting money in pension
schemes is usually mandatory.
(*) See that word. People usually know that they have to prepare for their
future, as a rational life goal. But circumstances, or the painful feeling that
discipline entails can deter them to follow their plan.
In stock markets, investors over-focus their attention on quarterly earnings.
This is a source of overtrading (see that word).
More generally, few investors have the strategy to "buy and hold" in order to
take advantage of the stock's long term prospects (well, if they are reliable).
This can lead to:
Either undervaluation of the stocks of some companies which
business model entails a long phase of business investment (research,
development, production facilities, large initial marketing expenses and low
margins to build market share) before reaching the full payoff.
The exception is when the market is bullish (see below the LT bias)
and looks for exceptional opportunities.
Or overvaluation of companies that under-invest for the future
and overexploit their current mother lode.
This ST bias that affects investors can create also a ST bias (short-termism)
in corporate management.
In this case the executives might lack vision in preparing the
company's strategy, or, instead of spending for the future of
the barn. would prefer to milk the cow (or in some cases to
take extravagant short term risk in the financial area)
The principal-agent problem (see that phrase) can be at play here, but also
4) Time horizon biases: what about the LT bias?
Diamonds are forever? Seeing money in eternity?
The opposite of the ST bias is the long term bias, in which
the time horizon is overly long.
This bias is less talked about, thus it can be more insidious. It might appear in stock valuation.
This happened in the Internet stock bubble.
Dotcom investors imagined huge profits, although impossible to estimate, in the far
future, for firms with nearly no paying customers and only costs for the years to come.
Predicting very long term growth is hazardous:
There can be illusions about the profit prospects of a new industry.
Even when its sales grow, a "make big money after a while" belief could be illusory.
Firms, industries and country economies suffer good or bad mutations, often
Even when they are rather stable, they tend to have a "life cycle" that can
end up in decline and death.
The longshot bias (see that phrase) is a slightly different phenomenon,
but which can have the same cause - an excessive time horizon.
It is an exaggerated trust in following a market uptrend or downtrend
even when it lasts for too long and leads to a gross overpricing or underpricing.
5) What is the lesson to draw for portfolio management?
And for market efficiency?
Time diversification is a possible strategy.
Time diversification is a wealth management technique in which investments
are spread into assets with different time horizons
and market cycles (see rotation).
To put eggs in different time baskets lowers the overall volatility and uncertainty.
Here, better warn about the market horizon bias:
When mimicry drives all investors to privilege the
same time horizon (usually a general quest for short term gains
n bubble periods, or for static investments in crash periods),
the market gets fully imbalanced , inefficient to allocate
resources and in high danger.
6) A few cents of philosophy ...with some real money consequences
Another thing is to ponder over the enigma of time and how we
Already we mentioned that the notion of short vs. long, when applied to time, is
seen differently according to people and situations, but there is more:
- Is time a continuous or a granular element of life? Also, is its line straight or
- Do people perceive / represent it:
As a flow that follows a regular direction?
Or as a circle / a rhythm (even an accordion)?
Or as a series of unvarying and mechanical sequences of precise time units:
hours, days, months, quarters, years, decades?
Do people, and among them investors, act in accordance with such mental
We might find examples of time rigidity (and regular granularity) in the "calendar
effect" (see that word).
Conversely, there are examples of time flexibility. Some quantitative analysts enter
a time adjustment in their models, with periods of time acceleration and others of
Again, such perceptions / representations of time can differ between various
civilizations, historical periods, and of course categories of economic players.
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