This document provides an overview of personal finance basics for engineers. It discusses how behavioral finance concepts like anchoring, mental accounting, and loss aversion affect financial decision making. It emphasizes the importance of cash flow, emergency funds, spending less than you earn, and the power of compound returns over long periods. The document recommends keeping investing simple through low-cost index funds and rebalancing annually.

1. FOR ENGINEERS
PERSONAL FINANCE
wealthfront.com
Adam Nash @adamnash
April 3, 2014

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Caveats & Preface
• I am not a financial planner
• This presentation is not financial advice
• You would be extremely foolish to make investment
decisions based solely on the content of this
presentation or discussion
• The opinions in this deck are intended purely to provoke
discussion & further education
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Why Personal Finance?
• Poorly covered in traditional education, even
top tier universities
• Not technically difficult, but signal:noise ratio
is terrible
• Massive impact on your life
- Money is one of the top 3 reasons
for marital problems
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Fast Five Finance Basics
1. Behavioral Finance Basics
2. Liquidity is Undervalued
3. Cash Flow Matters
4. The Magic of Compounding
5. Good Investing is Boring
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5. How many of you think
you are rational with
your money?
(show of hands)

6. You are NOT rational
ANCHORING MENTAL ACCOUNTING CONFIRMATION &
HINDSIGHT BIAS
GAMBLER’S FALLACY
OVERCONFIDENCEHERD BEHAVIOR OVERREACTION &
AVAILABILITY BIAS
LOSS AVERSION
(PROSPECT THEORY)

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Anchoring
• People estimate answers to new /
novel problems with a bias towards
reference points
• Example: 1974 Study
• Most common examples:
• Price you bought a stock at
• High point for a stock
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Mental Accounting
• Money is fungible, but people put it
in separate “mental accounts”
• Lost movie tickets example
• “Found Money” problem
• Vacation fund & credit card debt
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Confirmation & Hindsight Bias
• We selectively seek information
that support pre-existing
theories, and ignore / dispute
information that disproves them.
• We overestimate our ability to
predict the future based on the
“obviousness” of the past.
(example: real estate)
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Gambler’s Fallacy
• We see patterns in independent,
random chains of events
• We believe that, based on series
of previous events, an outcome is
more likely than odds actually
suggest
• Coin flip example
• It’s because with human behavior,
there are no “independent” events
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Herd Behavior
• We have a tendency to mimic the
actions of the larger group
• Crowd psychology is a major
contributor to bubbles (believed)
• Easier to be “wrong with everyone”
than “right and alone”
• No one gets fired for buying IBM?
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Overconfidence
• In one study, 74% of investment
managers believe they deliver
above average returns.
• Positively correlated with High IQ...
• Learn humility early
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Overreaction & Availability Bias
• Overreact to recent events
• Overweight recent trends
• Studies demonstrate that checking
stock prices daily leads to more
trading and worse results on
average
• Worse in high tech, because we
are immersed in “game changers”
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14. Choice B:
You have a 100% chance of gaining $500.
You have $1,000 and you must
pick one of the following choices:
Choice A:
You have a 50% chance of gaining $1,000,
and a 50% chance of gaining $0.

15. Choice B:
You have a 100% chance of losing $500.
Now, you have $2,000 and you must
pick one of the following choices:
Choice A:
You have a 50% chance of losing $1,000,
and a 50% chance of losing $0.

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Loss Aversion (aka Prospect Theory)
• We hate losses more than we love
winning
• Average loss aversion is 3:1 (!)
• Affects views on wide range of
situations, including taxes, holding
on to losing stocks, “sunk cost”
mistakes
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17. It’s OK to not be rational.

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It’s OK to Not Be Rational
• The key is that humans are predictably irrational
• Know your own flaws, and you can set up systems to
account for them
• Self-awareness is key
(yes, my Mom is a psychologist...)
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Liquidity
• Almost universally undervalued
• Strictly defined - it’s the
quantification of how much money
you can get, and how fast.
• Liquidity is the power to take
advantage of great investment
opportunities
• Liquidity is also, in the end, the
only thing that matters when you
need to pay for something.
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Liquidity & Returns
• In almost all cases, liquidity is inversely
correlated with returns
• Examples:
- Cash = very liquid
- Private equity = very illiquid
• Common mistake: Safety != Liquidity
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Practical Outcome: Emergency Funds
• Standard recommendation is that you
have 3-6 months of living expenses in
cash / cash-equivalents.
• That number increases if you are in
highly volatile industry / career.
• Worth considering length of time for
potential job search.
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Cash Flow
• The ultimate secret to personal finance is
quite simple:
- Spend less than you make
(on an ongoing basis)
• Very easy to measure, but few people do.
Annual budget is a great idea.
• Don’t forget to model in annual expenses
& “personal spending”
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Savings Targets
• What’s the right number? 3%? 6%?10%? 20%?
- There is no question - the more you save, the more
secure you are. Income comes & goes, but expenses
/ lifestyle are sticky!
• A lot of models assume working 40 years, and
producing savings to generate 80% of working
income.
- These models don’t actually match anyone’s real
world experience.
- There are a lot of models out there, and rules of
thumb, but it’s important to run the numbers yourself.
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The Magic of Compounding
• Not convinced that Albert Einstein said it was the
greatest force in the universe.
• It’s the key to almost all long term financial planning.
• Exponentials are bad in algorithmic cost, good in
savings returns.
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Simple Model
• Rule of 72
• In Excel, for each year, just use
=POWER(1+rate, year)
• 4% over 20 years is 2.19x
• 8% over 20 years is 4.66x
• Careful: it works on debt just as well as savings...
in reverse!
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The Benefits of An Early Start
• Compounding really takes off over long time periods
Years Return at 8%
10 2.16x
20 4.66x
30 10.06x
40 21.72x
50 46.9x
In most retirement planning
models, money saved between
ages 25 - 35 produces more
money than all savings between
35 - 65!
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The Dangers of Debt
• Bankruptcy is literally when you can’t pay your debts.
You can’t go bankrupt if you don’t have debt.
• You will never find an investment that pays 8%
guaranteed, let alone 20%+
• You will find *tons* of credit offers out there that will
charge you that.
• “Bad” debt is toxic, your best return is to pay it off.
But emergency fund takes precedence.
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Good Investing is Boring
• No one wants to be average, but with investing,
average is actually well above average.
• You will beat most mutual funds, and a large majority of
your peers with simple, low-cost index funds.
• Asset allocation explains ~90% of the variance between
fund performance
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Basic Asset Allocation
• Different types of assets (stocks, bonds, etc) have
different volatility & return characteristics
• There is an efficient frontier of combinations that
can maximize return for a given volatility
• Complication: historical performance does not
predict future performance
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Simple Operating Model
• 2 hours of work per year.
• Pick an asset allocation that is appropriate for your
emotional character & time frame & goals.
• For each asset class, pick the cheapest index fund with
the lowest drift and best liquidity.
• Rebalance every year.
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Recommended Books
• WSJ Guide to Understanding Money & Investing
• The Millionaire Next Door
• A Random Walk Down Wall Street
• The Essays of Warren Buffett
• Common Stocks & Uncommon Profits
• The Intelligent Investor
• Devil Take the Hindmost
• When Genius Failed
• Against the Gods: The Remarkable Story of Risk
• http://blog.adamnash.com/2007/02/14/personal-finance-
education-series-2-recommended-books/
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Disclosure
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Text
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