Goat Academy

Comprehensive guide

Stocks and Index Funds

The reference guide to equity investing. It moves from what a stock is, through how to research a company, to index funds, the S&P 500, mutual funds, thematic investing, portfolio construction, and the approaches investors use in different market conditions.

Goat Academy Editorial

16 min read

Investment fundamentals

A stock is a unit of ownership in a company. When you buy one, you own a fraction of the business, its assets, and its future profits. Companies issue stock to raise capital; investors buy it in the hope that the company grows, that it pays dividends, or both.

Stocks trade on exchanges where buyers and sellers are matched continuously during market hours. The price at any moment reflects the balance of what buyers are willing to pay and sellers willing to accept, which in turn reflects expectations about the company, its industry, and the economy.

The benefits of owning stocks are growth, dividend income, and a historical tendency to outpace inflation over long periods. The cost is volatility: prices fluctuate daily, and individual companies can fail.

Stocks versus bonds

A bond is a loan rather than an ownership stake. Bondholders receive fixed interest and are repaid at maturity, and they rank ahead of shareholders if a company fails. In exchange for that security, bonds have historically returned less than stocks over long periods. Most portfolios hold both, with the mix depending on time horizon and tolerance for volatility.

Getting started

Begin with a clear goal and a time horizon. Money needed within a few years should not be in stocks. Open a brokerage account with a regulated provider; most now have no minimum and no commission on stock trades. Fund it with an amount you can leave invested, and set up a recurring contribution so that investing becomes routine rather than an event.

Online platforms have made all of this straightforward. The Goat Academy guide to trading tools compares the widely used platforms and explains how to place a first order.

Researching a stock

Three numbers give a first impression of any company.

  • Revenue. Total sales. Growing revenue shows the business is expanding its market.
  • Earnings per share (EPS). Net profit divided by the number of shares. It shows how much profit each share is entitled to.
  • Price to earnings ratio (P/E). Share price divided by EPS. It shows how much investors are paying for each unit of profit, and is most useful compared against the company's own history and its peers.

Beyond the numbers, read the annual report to understand what the company does, who its competitors are, and what management says about risks. For a beginner, established companies with long records of profitability are easier to analyse than early stage businesses, and broad ETFs remove the need to analyse individual companies at all.

Index funds

An index fund holds all the securities in a market index in the same proportions as the index itself. It is passively managed: there is no manager deciding what to buy, only a rule to track the index. That simplicity produces the two main benefits of index funds, low cost and broad diversification. Annual fees on major index funds are often below 0.1%, compared with 1% or more for many actively managed funds.

The S&P 500

The S&P 500 is an index of 500 large companies listed in the United States, weighted by market capitalisation, so the largest companies have the greatest influence on its value. It is widely used as a benchmark for the US stock market as a whole. Investors gain exposure to it through index mutual funds or ETFs that track it, available from Vanguard, Fidelity, Schwab, BlackRock, and others.

Mutual funds

A mutual fund pools money from many investors and is priced once a day. Equity funds hold stocks, debt funds hold bonds, and hybrid funds hold both. Mutual funds can be active or passive. The distinction that matters most is cost: an actively managed fund has to outperform by more than its fee simply to match a passive alternative, and over long periods most do not.

Investing in artificial intelligence

Artificial intelligence has become a dominant theme in equity markets. Investors seeking exposure have two routes. The first is direct ownership of the large companies most involved in AI infrastructure and services, such as Alphabet, Nvidia, Microsoft, and Amazon. The second is thematic ETFs that hold a basket of AI related companies, for example the Global X Artificial Intelligence and Technology ETF (AIQ), the iShares Future AI and Tech ETF (IRBO), or the ARK Autonomous Technology and Robotics ETF (ARKQ).

Thematic investing concentrates risk in a single narrative. Valuations in popular themes can run well ahead of earnings, and enthusiasm can reverse quickly. An investor who wants AI exposure should size it as a satellite around a diversified core rather than the core itself. Goat Academy has published research on the capital flows behind this theme; see the resources page.

Building a portfolio

  • Think long term. The advantage an individual investor has over institutions is a time horizon measured in decades. Use it.
  • Start with what you have. Dollar cost averaging and fractional shares mean a modest monthly amount can be fully invested in a diversified fund from the first month.
  • Consider a robo adviser if you prefer not to make decisions. Services such as Betterment build and rebalance a diversified ETF portfolio for an annual fee.
  • Rebalance on a schedule. Once or twice a year, sell what has grown beyond its target weight and buy what has fallen below it.

Investment approaches and market conditions

Growth, value, and dividend investing

Growth investors buy companies expanding faster than the market, accepting high valuations for future earnings. Value investors buy companies trading below their estimated worth, often in unfashionable sectors. Dividend investors prioritise companies with reliable and growing payouts. Each approach has periods of outperformance and underperformance, and many investors blend them.

Bull, bear, and sideways markets

In a rising market the discipline is to stay invested and avoid chasing the strongest performers. In a falling market the discipline is to keep contributing, since every purchase is at a lower price, and to avoid selling at the point of maximum fear. In a sideways market, dividend income and periodic rebalancing do most of the work. The Goat Academy article on Felix Prehn's view of a new bull market discusses how the framework changes across regimes.

Learning resources

Books by Benjamin Graham, John Bogle, and Peter Lynch remain the standard introductions. Online communities such as the Bogleheads forum and investing subreddits are useful for questions, though the quality of advice varies widely. Podcasts and educational video channels, including the Felix Podcast, provide ongoing context. For structured learning, the Wall Street Protocol is Goat Academy's complete programme, and the free stock trading resources page lists what is available at no cost.

Key points

What to take from this guide

  • 01A stock is ownership; a bond is a loan. Most portfolios need both.
  • 02Revenue, EPS, and P/E give a first impression of a company; the annual report gives the rest.
  • 03Index funds tracking the S&P 500 offer diversification at very low cost and suit most long term investors.
  • 04Thematic exposure such as AI belongs as a satellite around a diversified core.
  • 05Discipline in bear markets, restraint in bull markets, and patience in sideways markets.

Goat Academy is an online financial education institution founded by economist and former investment banker Felix Prehn. It is published by Skillset Solutions FZ-LLC.

Goat Academy provides education only. Nothing on this site is financial, investment, or tax advice, and no outcome, return, or income is promised or implied. Trading and investing carry risk, including the loss of capital.

Questions about this page can be sent to [email protected].

Next steps

From understanding to method

The Wall Street Protocol teaches the complete process Felix Prehn uses to analyse companies, indices, and market regimes.