Investor's Glossary: essential terms

ETF (Exchange Traded Fund)
A fund that is bought and sold on the stock exchange like a share. It replicates an index (e.g., S&P 500) following predefined rules. Advantages: automatic diversification, low costs, transparency.

Index
A formula that decides which securities to include and with what weighting. Examples: MSCI World (global stocks), S&P 500 (500 US companies), FTSE MIB (leading Italian companies). The index is the recipe, the ETF is the dish that follows it.

PAC (Capital Accumulation Plan)
Investing a fixed amount at regular intervals (e.g., $200 per month). Reduces timing anxiety and smooths out purchase prices over time. Perfect for those who want discipline.

Cost Averaging By
investing periodically, the average purchase price stabilizes. If you buy when the price rises and when it falls, in the long run, the average price becomes more balanced than if you buy everything in one day.

PMC (Average Purchase Price)
The average price you paid for a position. Useful to know, dangerous to obsess over. Don't buy just to lower your PMC: buy because it's consistent with your plan.

TER (Total Expense Ratio)
The annual cost of managing an ETF or fund, expressed as a percentage (e.g., 0.20%). You don't pay it as a bill: it's already incorporated into the value of the fund and reduces your return.

Spread
The difference between the price at which you can buy (ask) and the price at which you can sell (bid) at a given moment. It is a market cost: the narrower (smaller) it is, the better it is for you.

Tracking Difference
The difference between the actual return of the ETF and that of the index it replicates. It derives from costs, management, and friction. A perfect ETF would have zero tracking difference (impossible in practice).

Physical
replication The ETF actually buys the securities in the index. It can be complete (all securities) or sampled (a representative subset). More transparent and intuitive.

Synthetic Replication (swap)
The ETF does not buy the securities directly, but uses contracts (swaps) to obtain the index return. It has a different risk profile (counterparty risk) but can have more accurate tracking.

Accumulation ETF
Automatically reinvests dividends or coupons. You do not receive money in your account, but the value of the shares increases. Promotes compound interest without manual actions.

Distribution ETF
Periodically pays dividends or coupons into your account. It is up to you to reinvest them if you want the compound effect. More flexibility, but requires discipline.

Buy & Hold
Buy and hold over time, avoiding impulsive trading. This does not mean never looking: it means having a plan and not reacting emotionally to every fluctuation.

Diversification
Don't put all your eggs in one basket. Spread your investments across different assets, sectors, and geographies to reduce overall risk. Caution: diversifying poorly (e.g., 10 similar ETFs) is not helpful.

Asset Allocation
How you divide your portfolio among different investment categories (stocks, bonds, cash, etc.). This is the most important decision: first decide how much risk you want, then choose the instruments.

Volatility
How much the price of an investment fluctuates. High volatility = large fluctuations. This is not risk in the traditional sense: it is short-term uncertainty. In the long term, volatility tends to smooth out.

Drawdown
The percentage loss from the historical high to the subsequent low. Example: the price goes from 100 to 70 = 30% drawdown. It tells you how much you can lose in the worst-case scenario.

Rebalancing Periodically
returning the portfolio to its initial asset allocation. If stocks have grown too much, sell some and buy bonds. Emotional discipline and risk management.

Decumulation
The phase in which you start to withdraw from your assets (e.g., in retirement). It is more delicate than accumulation: you need strategies to avoid running out of money too soon.

Return Sequence
Risk The risk that negative returns at the beginning of decumulation will ruin the sustainability of withdrawals. If you withdraw during a crisis, the damage is amplified. Solution: flexible withdrawal strategies.

Bias (behavioral finance) Mental
shortcuts that lead us to irrational decisions. Examples: FOMO (fear of missing out), loss aversion (the pain of losing outweighs the pleasure of gaining), sunk cost (I continue to invest because I have already put money in).

FOMO (Fear Of Missing Out)
The fear of missing out on an opportunity. It makes you buy when everyone else is buying, often at the worst possible time. Antidote: a written plan and discipline.

Loss Aversion
The pain of losing weighs more psychologically than the pleasure of gaining. Result: you sell your gains too early and hold on to your losses for too long.

Sunk Cost
You continue to invest or hold a position just because you've already put money into it. Irrational decision: what you've spent is lost, only the future matters.

Dividends
Periodic payments that some companies distribute to shareholders. They are not free money: when a company pays dividends, the share price falls accordingly.

Coupon
The periodic payment of interest on a bond. Example: a $1,000 bond with a 3% annual coupon = $30 per year.

Duration
Measures the sensitivity of a bond to changes in interest rates. The higher the duration, the more the price fluctuates when rates change. A key concept for bond investors.

Yield vs. Return
Yield is how much you earn as a percentage (e.g., +5%). Return is how much you earn in absolute terms (e.g., +€500). This distinction is useful for truly evaluating results.

Compound Interest
Earning interest on interest. It is the most powerful force in long-term investments. Example: €10,000 at 7% per annum becomes €19,672 in 10 years without adding anything.