RULE 3-5-7: Investor Trading Strategy

Posted on November 6, 2025 by Dr. David Edward Marcinko MBA MEd CMP™

By Dr. David Edward Marcinko MBA MEd

SPONSOR: http://www.MarcinkoAssociates.com

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The 3-5-7 Rule is a trading strategy that helps investors manage risk and maximize gains by setting clear limits on losses and targets for profits. It’s a simple yet powerful framework for disciplined decision-making.

In the volatile world of trading, success often hinges not just on identifying opportunities but on managing risk with precision. The 3-5-7 Rule is a widely respected risk management strategy designed to help traders protect their capital while pursuing consistent returns. This rule provides a structured approach to trading by setting specific thresholds for risk exposure and profit expectations.

At its core, the 3-5-7 Rule breaks down into three key components:

  • 3% Risk Per Trade: Traders should never risk more than 3% of their total account value on a single trade. This limit ensures that even if a trade goes against them, the loss is manageable and doesn’t jeopardize their overall portfolio.
  • 5% Total Exposure Across All Positions: The rule advises that total exposure across all open positions should not exceed 5% of the account value. This prevents over-leveraging and reduces the impact of correlated losses during market downturns.
  • 7% Profit Target: For every trade, the goal is to achieve a profit that is at least 7% greater than the potential loss. This risk-to-reward ratio helps ensure that even with a lower win rate, traders can remain profitable over time.

The beauty of the 3-5-7 Rule lies in its simplicity and adaptability. It can be applied across various asset classes—stocks, forex, crypto—and suits both beginners and seasoned traders. By enforcing discipline, it helps traders avoid emotional decisions, such as chasing losses or holding onto losing positions too long. Moreover, this rule encourages thoughtful position sizing. Traders must calculate their entry and exit points carefully, factoring in stop-loss levels and account size. This analytical approach fosters better trade planning and reduces impulsive behavior.

Another advantage is its scalability. As a trader’s account grows, the percentages remain constant, but the dollar amounts adjust accordingly. This keeps the strategy relevant and effective regardless of portfolio size. In practice, the 3-5-7 Rule acts as a safety net. It doesn’t guarantee profits, but it significantly reduces the likelihood of catastrophic losses. It also promotes consistency, which is crucial for long-term success in trading.

In conclusion, the 3-5-7 Rule is more than just a guideline—it’s a mindset. It teaches traders to respect risk, plan strategically, and aim for favorable outcomes.

By adhering to this rule, traders can navigate the unpredictable markets with greater confidence and control.

COMMENTS APPRECIATED

EDUCATION: Books

SPEAKING: Dr. Marcinko will be speaking and lecturing, signing and opining, teaching and preaching, storming and performing at many locations throughout the USA this year! His tour of witty and serious pontifications may be scheduled on a planned or ad-hoc basis; for public or private meetings and gatherings; formally, informally, or over lunch or dinner. All medical societies, financial advisory firms or Broker-Dealers are encouraged to submit an RFP for speaking engagements: CONTACT: Ann Miller RN MHA at MarcinkoAdvisors@outlook.com 

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Understanding Parkinson’s Law: Importance vs Attention

Posted on November 6, 2025 by Dr. David Edward Marcinko MBA MEd CMP™

The Attention a Problem Gets is Inverse to its’ Importance

Courtesy: http://www.CertifiedMedicalPlanner.org

By Dr. David Edward Marcinko MBA, MEd CMP

Historian Cyril Parkinson’s wrote in his book Parkinson’s Law,

“The time spent on any item of the agenda will be in inverse proportion to the sum [of money] involved.”

EXAMPLE: Parkinson described a fictional finance committee with three tasks: approval of a $10 million nuclear reactor, $400 for an employee bike shed, and $20 for employee refreshments in the break room.

The committee approves the $10 million nuclear reactor immediately, because the number is too big to contextualize, alternatives are too daunting to consider, and no one on the committee is an expert in nuclear power.

Bike Shed Effect: The bike shed gets considerably more debate. Committee members argue whether a bike rack would suffice and whether a shed should be wood or aluminum, because they have some experience working with those materials at home.

Employee refreshments take up two-thirds of the debate, because everyone has a strong opinion on what’s the best coffee, the best cookies, the best chips, etc.

Absurd: The world is filled with these absurdities. In personal finance, Ramit Sethi recently said we should stop asking $3 questions (should I buy coffee?) and ask more $30,000 questions (should I buy a smaller home?). Most people don’t, because it’s hard and intimidating. In any given moment the easiest way to deal with a big problem is to ignore it and fill your time thinking about a smaller one.

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Assessment: Your thoughts and comments related to the post Corona Virus Pandemic, meetings and time management and psychology are appreciated.

THANK YOU

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Understanding Goodhart’s Law and Its Impact on Healthcare Artificial Intelligence

Posted on November 6, 2025 by Dr. David Edward Marcinko MBA MEd CMP™

By Staff Reporters and Copilot A.I.

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Goodhart’s law is an adage often stated as, “When a measure becomes a target, it ceases to be a good measure”. It is named after British economist Charles Goodhart, who is credited with expressing the core idea of the adage in a 1975 article on monetary policy in the United Kingdom:

Any observed statistical regularity will tend to collapse once pressure is placed upon it for control purposes.

It was used to criticize the British Margaret Thatcher Government for trying to conduct monetary policy on the basis of targets for broad and narrow money, but the law reflects a much more general phenomenon.

And so, aother famous Goodhart’s Law example is the cobra effect, where well-intentioned government policies inadvertently worsened the problem they were designed to solve.

For example, the British colonial government in India, concerned about the increasing number of venomous cobras in Delhi, began offering a bounty for each dead cobra that was delivered. Initially, this strategy was successful as locals brought in large numbers of slaughtered snakes. Over time, however, enterprising individuals started breeding cobras to kill them for supplemental income. When the government abandoned the bounty, the cobra breeders released their cobras into the wild, leading to a surge in Delhi’s snake population.

The cobra effect, where efforts to control a problem lead to unintended and often worse outcomes, serves as a cautionary tale for health care AI. If developers or health care institutions focus too narrowly on specific performance AI metrics, they risk undermining the system’s overall effectiveness, leading to suboptimal patient outcomes. Physicians must be vigilant in ensuring that health care AI systems are not only optimized for performance metrics but are also truly beneficial in practical, clinical applications.

Modified: Dr. Neil Anand via Kevin MD

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HIGH-FREQUENCY TRADING: Algorithmic Computerized Stock Trading

Posted on November 6, 2025 by Dr. David Edward Marcinko MBA MEd CMP™

By Dr. David Edward Marcinko MBA MEd

SPONSOR: http://www.MarcinkoAssociates.com

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High-frequency trading (HFT) is a form of algorithmic trading that uses powerful computers and complex programs to execute thousands of trades in fractions of a second. It has transformed modern financial markets by increasing speed, liquidity, and efficiency—but also raised concerns about fairness and stability.

High-frequency trading emerged in the early 2000s as technological advances allowed financial firms to process market data and execute trades faster than ever before. HFT firms use sophisticated algorithms to analyze multiple markets and identify short-term opportunities. These trades are often held for mere seconds or milliseconds, and profits are made by exploiting tiny price discrepancies across assets or exchanges.

One of the defining features of HFT is its reliance on speed. Firms invest heavily in infrastructure—such as co-location services near exchange servers and fiber-optic cables—to gain microsecond advantages over competitors. This race for speed has led to a technological arms race, where milliseconds can mean millions in profit.

HFT contributes significantly to market liquidity, meaning it helps ensure that buyers and sellers can transact quickly at stable prices. By constantly placing and updating orders, HFT firms narrow bid-ask spreads and reduce transaction costs for other market participants. This has made markets more efficient and accessible, especially for retail investors.

However, HFT is not without controversy. Critics argue that it creates an uneven playing field, where firms with access to advanced technology and capital can dominate markets. Concerns about market manipulation—such as quote stuffing (flooding the market with orders to slow competitors) or spoofing (placing fake orders to move prices)—have led to increased regulatory scrutiny.

The 2010 Flash Crash is often cited as a cautionary example of HFT’s potential risks. During this event, the Dow Jones Industrial Average plunged nearly 1,000 points in minutes before rebounding. Investigations revealed that automated trading systems, including HFT algorithms, contributed to the sudden loss of liquidity and extreme volatility.

Regulators have responded by implementing safeguards such as circuit breakers, which pause trading during extreme price movements, and requiring firms to register and disclose their trading strategies. The Securities and Exchange Commission (SEC) and Commodity Futures Trading Commission (CFTC) continue to monitor HFT’s impact on market integrity.

Despite its challenges, HFT remains a dominant force in global finance. It accounts for a significant portion of trading volume in equities, futures, and foreign exchange markets. Many institutional investors rely on HFT strategies to manage large portfolios and hedge risks.

In conclusion, high-frequency trading represents both the promise and peril of technological innovation in finance. While it enhances market efficiency and liquidity, it also introduces new risks and ethical dilemmas.

As markets evolve, balancing innovation with fairness and stability will be essential to ensuring that HFT serves the broader interests of investors and the economy.

COMMENTS APPRECIATED

EDUCATION: Books

SPEAKING: Dr. Marcinko will be speaking and lecturing, signing and opining, teaching and preaching, storming and performing at many locations throughout the USA this year! His tour of witty and serious pontifications may be scheduled on a planned or ad-hoc basis; for public or private meetings and gatherings; formally, informally, or over lunch or dinner. All medical societies, financial advisory firms or Broker-Dealers are encouraged to submit an RFP for speaking engagements: CONTACT: Ann Miller RN MHA at MarcinkoAdvisors@outlook.com 

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