True investment maturity isn't about holding through drawdowns. It's about recognizing when new information invalidates your thesis and selling immediately. The common instinct to defend a position by buying more is a costly mistake that turns event-driven plays into distressed holdings.
Regularly re-evaluate your investment theses. Stubbornly holding onto an initial belief despite new, contradictory information can lead to significant losses. This framework encourages adaptation by forcing you to re-earn your conviction at regular intervals, preventing belief calcification.
Combat indecision and emotional attachment by pre-committing to sell an investment if it fails to meet a specific metric (the state) by a specific deadline (the date). This creates a pre-commitment contract that closes long feedback loops and prevents complacency with underperforming assets.
The best macro traders (Jones, Druckenmiller, Soros) are defined by their ability to discard a viewpoint the moment facts change, rather than defending it out of ego. This intellectual flexibility is crucial for survival and success, as clinging to a wrong idea is a far greater error than admitting a mistake.
To avoid emotional, performance-chasing mistakes, write down your selling criteria in advance and intentionally exclude recent performance from the list. This forces a focus on more rational reasons, such as a broken investment thesis, manager changes, excessive fees, or shifting personal goals, thereby preventing reactionary decisions based on market noise.
Successful investing requires strong conviction. However, investors must avoid becoming so emotionally attached to their thesis or a company that they ignore or misinterpret clear negative signals. The key is to remain objective and data-driven, even when you believe strongly in an investment.
Contrary to the 'hold forever' value investing trope, a three-year period of underperformance is a strong signal that your initial thesis was flawed. It's better to admit the mistake and reallocate capital than to stubbornly wait for the market to agree with you.
Before committing capital, professional investors rigorously challenge their own assumptions. They actively ask, "If I'm wrong, why?" This process of stress-testing an idea helps avoid costly mistakes and strengthens the final thesis.
McCullough advocates for a "promiscuous" investment strategy, quickly moving capital to where signals are strongest. He argues that emotional attachment to winning positions, or "bag holding," is the primary way investors lose ground. The goal is to compound returns by avoiding drawdowns, not by marrying a single investment thesis.
To survive long-term, systematic trading models should be designed to be more sensitive when exiting a trade than when entering. Avoiding a leveraged liquidity cascade by selling near the top is far more critical for capital preservation than buying the exact bottom.
While having a disciplined rule like reviewing a stock after 24 months is useful, it should be subordinate to a more critical rule: sell immediately if the fundamental investment thesis breaks. This flexibility prevents holding onto a losing position simply to adhere to a predefined timeline.