I put 80% of my money in the S&P after Howard Marks told me not to

Your financial success isn't about market timing or complex strategies—it's about knowing your psychological biases and building systems to work with them, not against them. The Swedish twin study revealed that 45% of investing behavior is genetic, but the winning move isn't fighting your nature—it'

May 11, 2026 1h 4m
My First Million

Key Takeaway

Your financial success isn't about market timing or complex strategies—it's about knowing your psychological biases and building systems to work with them, not against them. The Swedish twin study revealed that 45% of investing behavior is genetic, but the winning move isn't fighting your nature—it's finding games that match your personality and creating pre-commitments so your future self can't sabotage your plan.

Episode Overview

Sam and Sean explore a Swedish twin study revealing that 45% of investing behavior is genetically determined, then dive into how self-awareness about personality type determines success more than financial knowledge. They discuss how the best investors treat finance as a study of human nature, share frameworks for matching your work to your psychological wiring, and reveal why reading books might help investors simply by keeping them from over-trading.

Key Insights

Your Business Problems Mirror Your Personality Defects

The issues you encounter in your company are direct reflections of your psychological patterns. If you have trust issues, your team will feel micromanaged. If you struggle with commitment, they'll think you're absent-minded. Your company culture and operational challenges are extensions of who you are as a person.

45% of Financial Behavior Is Genetic—But You Control the Other 55%

A 2014 Swedish study tracking twins found that genetics accounts for 45% of investing patterns and behaviors—similar to controlling your height. However, this means 55% is still within your control. The key isn't fighting your genetic predisposition but understanding it and building systems around it.

Change Requires Pain, Not Just Reading

The Swedish study found that once normalized for education, reading more investing books didn't make people better investors. The only factor that created meaningful change was actually working in finance and experiencing real losses. You have to burn your hand, not just read about burning it.

Match Your Game to Your Personality Type

Monish Pabrai discovered through personality assessment that he thrives in 'solo player competitive number-based games'—which explains why he excelled at investing but struggled running a team-based company. Success comes from identifying what type of game you're naturally wired for, then finding yourself in those situations.

Too Many Ideas Can Destroy Your Company

Jeff Bezos learned that releasing too many ideas creates backlogs, distractions, and work-in-process that adds no value. Even great ideas, released at the wrong rate, can suffocate an organization. The solution is learning to prioritize and release work at the rate your organization can actually absorb it.

Notable Quotes

"Personal finance is more personal than it is finance."

— Sam Parr (quoting Morgan Housel)

"Change requires pain, not words."

— Sam Parr

"You have enough ideas per minute, per day, per week to destroy Amazon. You have to figure out how to release the work at the right rate that the organization can accept it."

— Jeff Wilkey (quoted by Sean Puri)

"The question is not what is the situation—it's what do I need to believe in order to do the things that will lead to a good result. What's useful is what matters."

— Sean Puri

Action Items

  • 1
    Identify Your Personality Type and Match It to Your Work

    Take a comprehensive personality assessment (like the one Monish Pabrai used) that involves input from coworkers, family, and friends. Identify whether you prefer solo vs. team activities, competitive vs. collaborative environments, and number-based vs. creative work. Then audit your current business and career to see if they align with these natural preferences.

  • 2
    Pre-Commit to Prevent Future Self-Sabotage

    Before making major decisions, write down your criteria and commit to them in advance. For example, if hiring someone, write down the exact metrics they must hit by month three and commit to firing them if they don't—regardless of how you feel in the moment. This removes emotional decision-making when you're 'hungry at the grocery store.'

  • 3
    Create a Weekly 'Ideas Container' Meeting

    Set up a dedicated weekly meeting (like Sam and Joe's Thursday session) where you can dump all ideas into a running list. This prevents you from releasing ideas in real-time via Slack or email, which creates overwhelming backlogs for your team. Release ideas at the rate your organization can absorb them.

  • 4
    Shorten Your Feedback Loops

    Design systems where you can see results quickly—like seeing points on a scoreboard. This allows you to get new information fast and adjust behavior before genetic biases compound into major problems. The faster you see consequences, the faster you can course-correct.

  1. Podcasts
  2. Browse
  3. I put 80% of my money in the S&P after Howard Marks told me not to