Ten MF mistakes I recommend you avoid...

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Get a cup of coffee.

In this thread, we'll cover *State Quantities* and *Flow Quantities*.

This mental model can help us analyze many different entities -- from complex engineering systems to publicly traded companies.

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A "State Quantity" is something that's associated with a *specific point in time*.

For example, the number of followers a Twitter account has is a state quantity. This number can go up and down over time. But at any one *specific* time point, it's fixed.

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Similarly, the amount of cash a company has is a state quantity.

This cash balance can also rise and fall over time.

But pick any one *specific* time point -- and the company can only have one *specific* cash balance at that time point.

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By contrast, a "Flow Quantity" is something that's associated with a time *interval* rather than a time *point*.

For example, the number of followers gained by a Twitter account is a flow quantity. It's meaningful only when we specify a time interval (eg, the last 30 days).

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A simple analogy is that a State Quantity is like a photo -- a snapshot at a particular *point* in time.

But a Flow Quantity is like a video -- a record of events that take place during a particular time *interval*.

Our intuitions often leads us astray. A good reminder: study counterintuitive math and economic results.

Here are 9 of them 🧵

The Birthday Paradox

In a room of 23 people, there's a >50% chance that 2 people share the same birthday.

This type of probabilistic thinking does *not* come naturally to many people.

The Coastline Paradox

Fractal geometry is also confounding:

The coastline of a landmass does not have a well-defined measurement. As the unit of measurement gets smaller (eg. from KMs to cm), the length increases without limit.

Winner's Curse

In an auction, the winning bid will usually exceed the intrinsic worth of an item leading to a significant overpay (and negative net profit for the winner).

Braess's Paradox

Removing an extra road can make everyone's commute time faster.

Why? The existence of a "fast" road leads to congestion because everyone uses it. If you remove the shortcut, traffic flows better.

The British Railway Mania

How a disruptive technology created the biggest speculative bubble in the history of England

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1/ Railways were the most disruptive technology of the 19th century, known as the "railway age", transforming England from an agricultural to an industrialized nation.

2/ The development of railway infrastructure and locomotives started at the end of the 18th century but experienced immense growth after 1830.

3/ Hundreds of railway related bills were passed every year with proposed rails totaling 10,000 miles, a third of which was never built due to poor financial planning, competition, or fraud.

4/ In the mid-1840s, the Bank of England cut interest rates rendering government bonds unattractive, and investors more willing to rush in the railway investments.

10 Key Takeaways from the book: The Emotionally Intelligent Investor

1. Investing success does NOT come from ignoring or suppressing emotion. Assuming that you have relevant expertise, disregarding intuition and empathetic feelings because they cannot be explained, is a mistake!

2. Self-awareness is the first and most important step in improving as an investor. An investment approach needs to fit with your unique set of motivations, personality traits, weaknesses, and strengths. Don’t try to be exactly like Warren Buffett if you are not like him!

3. Humans have certain common investing vulnerabilities, but everybody is unique in their susceptibility to them. Consider your weaknesses to be the investing biases and traps to which you are most prone.

4. Because we are constantly changing, introspection should be incorporated into the daily and weekly routines of any investor. Try writing in a trading/Investing journal.

A potential problem is looming, and the media are pursuing a new story that builds on the following chain of reasoning: 1) higher inflation is coming;2) if CBs increase interest rates debts will explode and recession may ensue; 3) CBs are caught in an impossible dilemma 1/12

It´s perhaps too complex for some tweets, but.. Registered inflation this year is bound to be higher than present forecasts, resulting from one-off price spikes and base effects That will not start a sustained high inflation process, but temporary higher inflation is possible 2/

For example, Euro Area inflation increased suddenly from several months at -0.3% to +0.9% in Jan. This jump resulted mostly from several base effects, especially the change to German VAT. Inflation expectations increasing but higher in the US than in the EA 3/

The major one-off base effect will come from oil prices that decreased abysmally in March 2020 and have recovered. Some estimates put US inflation in April reaching 4%! After vaccinations, later in the year, pent-up consumer demand will also increase prices.4/

Despite the increased spending of accumulated savings, the savings rate will remain higher than before Covid for precautionary reasons (Fig 1). No permanent spending spree will materialise. Wages will remain subdued for a while (Fig2). Higher but not high inflation is coming.5/