Stocks and Bonds: How Stocks, Bonds, Funds, ETFs and Treasuries Work
In Short
Stocks and Bonds are the two building blocks of most investment portfolios: stocks are shares of ownership in a company, and bonds are loans to a government or company that pay interest. They are commonly held directly or through mutual funds and ETFs by people saving for long-term goals such as retirement.
TL;DR
- Stocks offer growth potential and dividends but can fall sharply; there is no assurance a company will do well [1].
- Bonds pay interest and return principal at maturity, but face credit, interest-rate, inflation, liquidity and call risk [2].
- Asset allocation and diversification spread money across and within asset classes to manage risk [3].
- Small differences in annual fees compound into large differences in ending value over decades [4].
- SIPC protects customers when a member brokerage fails, but not against market losses; FDIC insurance does not cover stocks, bonds or funds [6][7].
Quick Facts
| Complexity | Medium |
|---|---|
| Setup Cost | Low — a brokerage or retirement account; fund expenses and any advisory fees apply |
| Time to Implement | A day or two to open an account; ongoing reviews and rebalancing |
| Illustrative Example | Illustrative example, not a projection. Investor.gov illustrates a $100,000 investment growing 4% a year for 20 years. With a 0.25% annual fee it ends near $208,000; with a 1.00% fee it ends near $179,000. The roughly $29,000 gap comes only from fees. Actual returns vary and can be negative. |
Key Numbers & Limits
| Item | Limit or Rule | Notes |
|---|---|---|
| SIPC Protection (Brokerage Failure) | Up to $500,000, including a $250,000 limit for cash | Does not cover declines in market value [6]. |
| FDIC Deposit Insurance | Does not cover stocks, bonds, mutual funds or Treasury securities | FDIC insures deposits, at least $250,000 per depositor, per ownership category, per bank [7]. |
| I Bond Purchase Limit | Up to $10,000 in electronic I bonds per Social Security number per calendar year | Electronic only since January 1, 2025 [5]. |
| I Bond Holding Rules | Redeemable after 12 months; cashing in before 5 years forfeits the last 3 months of interest | Earns interest for up to 30 years [5]. |
| Long-Term Holding Period | More than one year | Shorter holdings produce short-term gains taxed as ordinary income [8]. |
| Long-Term Capital Gain Rates (2025) | 0%, 15% or 20%, depending on taxable income | For 2025, the 0% rate applies up to $48,350 (single) or $96,700 (married filing jointly) of taxable income [8]. |
| Capital Loss Deduction Against Other Income | $3,000 per year ($1,500 if married filing separately) | Unused losses carry forward [8]. |
What Is Stocks and Bonds?
Stocks and bonds are the two most widely held types of securities. A stock, also called an equity, is a share of ownership in a company; investors buy stocks for possible price growth, dividends and voting rights [1]. A bond is a debt security, like an IOU: the investor lends money to a government, municipality or corporation, which promises to pay interest and repay the principal at maturity [2].
Mutual funds and exchange-traded funds (ETFs) are investment companies that pool money from many investors and buy stocks, bonds and other assets, so one share gives a small stake in many holdings [3]. A fund that focuses on a single industry may not provide much diversification [3].
U.S. Treasury securities are issued by the Treasury and backed by the full faith and credit of the U.S. government; they include bills, notes, bonds and Treasury Inflation-Protected Securities (TIPS) [2]. Series I savings bonds are non-marketable Treasury bonds bought through TreasuryDirect whose rate combines a fixed rate and an inflation rate that resets every six months [5].
How these pieces are combined is called asset allocation: dividing investments among stocks, bonds and cash based on time horizon and risk tolerance [3].
How Does Stocks and Bonds Work?
- An investor opens an account at a brokerage firm, a fund company, a workplace retirement plan or TreasuryDirect, depending on what is being bought [5].
- The investor chooses an asset allocation — a mix of stocks, bonds and cash — that fits the time horizon and willingness to accept losses [3].
- Within each asset class, money is spread across many companies, issuers and sectors, often through mutual funds or ETFs [3].
- Over time, holdings drift as some grow faster than others; rebalancing sells some of what has grown and adds to what has lagged to restore the target mix [3].
- Dividends, interest and gains are taxed each year in a taxable account. Assets held more than one year qualify for long-term capital gain rates when sold [8]. Tax-advantaged accounts such as IRAs and 401(k)s follow their own rules on contributions and withdrawals.
The Good: What Are the Benefits of Stocks and Bonds?
- Investor.gov notes that stocks have offered the greatest potential for growth over long periods and that investors who held them for periods such as 15 years have generally been rewarded, although past results do not assure future ones [1].
- Bonds can provide a predictable income stream and help offset more volatile stock holdings; bonds held to maturity return their face value if the issuer does not default [2].
- Funds and ETFs make broad diversification available with small amounts of money [3].
- Treasury securities carry the full faith and credit of the U.S. government, and I bond interest is exempt from state and local income tax [2][5].
- Listed stocks, bonds and funds can usually be sold on any business day, unlike real estate or private businesses.
The Bad: What Are the Drawbacks of Stocks and Bonds?
- Stock prices move down as well as up, sometimes for years, and an investor can lose money [1].
- Bond prices fall when interest rates rise, so a bond sold before maturity may be worth less than its face value [2].
- Inflation reduces the purchasing power of fixed interest payments [2].
- Fees that look small — fund expenses, advisory fees, sales loads — compound over time and reduce ending value [4].
- Mutual funds are not insured by the FDIC or any other government agency [7].
- I bonds cannot be cashed in for the first 12 months, and cashing in before 5 years forfeits 3 months of interest [5].
The Ugly: What Are the Serious Risks of Stocks and Bonds?
- Concentration in one company, including an employer's stock, can mean a permanent loss if that company fails; diversification exists to reduce this risk [3].
- Bond issuers can default on interest or principal; lower-rated, high-yield bonds carry more credit risk [2].
- Fraudsters sell unregistered bonds and stocks or run pump-and-dump schemes; registered public offerings can be checked on the SEC's EDGAR system [2].
- SIPC does not protect against market losses or investments sold by firms that are not SIPC members [6].
Who Uses Stocks and Bonds?
Who It's Commonly Used By
Who It's Generally Not Suited For
- Money needed within a short time frame, where a stock market decline could force a sale at a loss [3].
- Emergency savings, which are commonly kept in FDIC-insured deposits rather than securities [7].
- Investors who would sell in a panic during a downturn and have not set an allocation they can stay with.
What Are the Key Rules & Requirements for Stocks and Bonds?
- Public offerings of stocks and corporate bonds are registered with the SEC; filings can be reviewed on EDGAR [2].
- SIPC protects customers of failed member firms up to $500,000, including $250,000 for cash, and does not protect against market losses [6].
- FDIC deposit insurance covers deposits, not stocks, bonds, mutual funds, annuities or Treasury securities [7].
- I bonds: up to $10,000 electronic per Social Security number per calendar year, redeemable after 12 months, with a 3-month interest penalty if cashed before 5 years; interest is subject to federal but not state or local income tax [5].
- Gains on assets held more than one year are long-term and taxed at 0%, 15% or 20%; gains on assets held one year or less are taxed as ordinary income [8].
- Net capital losses offset up to $3,000 of other income a year ($1,500 married filing separately), with the rest carried forward [8].
What Are Common Mistakes & Red Flags With Stocks and Bonds?
- Choosing funds based only on past returns while ignoring expense ratios and sales loads [4].
- Holding several funds that own the same top holdings and assuming that is diversification [3].
- Buying bonds or notes from someone selling unregistered securities [2].
- Not rebalancing for years, so the portfolio's risk drifts far from the original plan [3].
- Opening an account with a firm that is not a SIPC member, or making checks payable to a sales representative [6].
- Selling winners in a taxable account without considering the holding period and tax rate [8].
Frequently Asked Questions
What Is the Difference Between Stocks and Bonds?
A stock is a share of ownership in a company, so its value depends on how the company performs [1]. A bond is a loan to an issuer that pays interest and returns principal at maturity, so its main risks are default, rising interest rates and inflation [2].
What Is the Difference Between a Mutual Fund and an ETF?
Both are investment companies that pool money to buy many securities [3]. Mutual fund shares are bought from and sold back to the fund at the day's net asset value, while ETF shares trade on an exchange throughout the day like a stock. Both charge annual expenses that reduce returns [4].
Is My Brokerage Account Insured?
If a brokerage firm that is a SIPC member fails, customers' cash and securities may be protected up to $500,000, including $250,000 for cash [6]. SIPC does not cover losses from a decline in market value, and FDIC deposit insurance does not cover stocks, bonds or mutual funds [6][7].
Why Do Bond Prices Fall When Interest Rates Rise?
When rates rise, newly issued bonds pay more interest, so an older bond with a lower rate is less attractive and typically sells at a discount. Holding the bond to maturity still returns its face value if the issuer does not default [2].
How Do I Bonds Work?
Series I savings bonds are bought electronically through TreasuryDirect. Their rate combines a fixed rate with an inflation rate that resets every six months, interest compounds semiannually, and each Social Security number can buy up to $10,000 a calendar year. They can be cashed after 12 months, with 3 months of interest forfeited if cashed before 5 years [5].
Sources
- Stocks — FAQs — U.S. Securities and Exchange Commission (Investor.gov)
- Bonds — FAQs — U.S. Securities and Exchange Commission (Investor.gov)
- Asset Allocation and Diversification — U.S. Securities and Exchange Commission (Investor.gov)
- Understanding Fees — U.S. Securities and Exchange Commission (Investor.gov)
- I Bonds — U.S. Department of the Treasury (TreasuryDirect)
- Securities Investor Protection Corporation (SIPC) — U.S. Securities and Exchange Commission (Investor.gov)
- Understanding Deposit Insurance — Federal Deposit Insurance Corporation
- Topic No. 409, Capital Gains and Losses — Internal Revenue Service
Primary sources only: the Internal Revenue Code, Treasury regulations and official agency guidance. Read how Zentavos researches these reports.