What Investment Companies Do and How They Work

An investment company pools money from many individual and institutional investors and puts that combined capital to work in a professionally managed portfolio of stocks, bonds, or other securities. What investment companies do, in plain terms, is give ordinary people access to a diversified, managed portfolio they could not practically build on their own, while handling the trading, recordkeeping, tax reporting, and regulatory compliance behind the scenes. As of 2024, U.S. registered investment companies managed roughly $41.5 trillion across nearly 13,700 funds.¹

Pooling Money and Managing It for You

The defining feature is aggregation. Thousands of participants each contribute money, and the company combines it into a single pool with far more purchasing power than any one person could generate. Your ownership stake is proportional to what you put in. If the pool holds $100 million in assets and you contributed $10,000, you own 0.01% of the portfolio.

That structure opens doors. Many bonds trade in minimum denominations of $100,000 or more, and building a properly diversified stock portfolio from scratch takes significant capital. By pooling resources, someone investing a few hundred dollars gets exposure to hundreds of different securities, and the costs of trading, research, and compliance are spread across the whole investor base.

On top of the pool sits a professional investment adviser or portfolio management team. They decide what the fund buys, sells, and holds, bound by the fund’s stated investment objective, which spells out permissible asset types and risk levels. A fund with a large-cap growth objective, for example, is not going to be loading up on speculative penny stocks. Active managers analyze individual companies and adjust holdings frequently, trying to beat the market. Passive managers simply replicate a benchmark index and trade only when the index itself changes. The approach you choose affects both your fees and the kind of returns you can expect.

The Three Types You’ll Encounter

Federal law recognizes three broad categories of investment companies, and the type you invest in determines how you buy and sell shares, what you pay, and how liquid your position is.

Mutual Funds (Open-End Management Companies)

The most common type. An open-end fund continuously issues new shares to anyone who wants to buy and redeems them directly when an investor wants to sell. The price for both transactions is the fund’s net asset value, calculated once at the end of each trading day.²

Closed-End Funds

A closed-end fund raises money through an initial public offering, issues a fixed number of shares, and then those shares trade on a stock exchange like any other listed security. Because supply is fixed, the market price often drifts above or below the fund’s actual net asset value, creating premiums or discounts that do not exist with mutual funds.³

Exchange-Traded Funds

ETFs blend features of both. Most are registered as open-end management companies, but their shares trade throughout the day on stock exchanges at market prices. Retail investors do not buy or redeem shares directly from the fund. Large financial institutions called authorized participants create and redeem shares in bulk blocks, which keeps the market price close to the underlying net asset value.² That same mechanism tends to make ETFs more tax-efficient than mutual funds holding similar assets.

Unit Investment Trusts

A unit investment trust holds a fixed portfolio of securities chosen at the outset and generally does not trade them afterward. There is no portfolio manager making ongoing decisions. The trust holds its original basket until a predetermined termination date, then liquidates and returns the proceeds to investors.⁴

What You Pay to Use One

Investment companies are not free. Every fund charges an expense ratio, expressed as an annual percentage of your assets in the fund. It covers the adviser’s management fee, administrative costs, legal and accounting expenses, and operational overhead. The asset-weighted average across all U.S. mutual funds and ETFs was about 0.34% in 2024, but the range is enormous. Passively managed index funds often charge around 0.10% or less, while actively managed stock funds commonly charge anywhere from 0.50% to over 1.00%.

Some funds also charge 12b-1 fees, which cover marketing and distribution. FINRA caps these at 0.75% of average annual net assets for distribution and an additional 0.25% for shareholder servicing, for a combined ceiling of 1.00%.⁵ Not every fund charges them, but when they exist, they are built into the expense ratio you see reported.

Fees compound. A 1% annual fee on a $50,000 investment over 20 years, assuming 7% annual growth, eats roughly $28,000 in returns compared to a fund charging 0.10%. The prospectus breaks out every component of the expense ratio, so checking it before you invest is one of the most consequential things you can do.

How You Get Paid and Taxed

Most investment companies are structured as regulated investment companies under Subchapter M of the Internal Revenue Code, which lets them avoid paying corporate-level income tax on earnings they pass through to shareholders. In exchange, the fund must distribute at least 90% of its investment company taxable income and 90% of its net tax-exempt interest income to shareholders each year.⁶

In practice, that means funds make regular distributions, usually quarterly or annually, consisting of dividends from stocks held, interest from bonds, and realized capital gains from securities the manager sold at a profit. You owe tax on these distributions even if you reinvest them rather than take cash. Here is the part that catches first-time fund investors off guard: you can owe tax on gains the fund realized during the year even if the overall value of your investment went down.

ETFs sidestep some of this because their in-kind creation and redemption process lets them shed low-cost-basis securities without triggering a taxable sale, which usually means fewer capital gain distributions passed to shareholders.²

At tax time, the fund issues Form 1099-DIV to every investor who received $10 or more in dividends or other distributions during the year. The form breaks out ordinary dividends, qualified dividends eligible for lower tax rates, capital gain distributions, and any foreign tax the fund paid on your behalf.⁷

What You Receive as a Shareholder

Before you can buy shares, the fund must deliver a prospectus disclosing fees, risks, investment strategy, and past performance. That is a legal obligation under the Securities Act.⁸

After you invest, you receive semi-annual and annual reports detailing financial condition, portfolio holdings, and performance. Funds may satisfy this by posting reports on a website and mailing shareholders a paper notice explaining how to access them, but any shareholder can request a full paper copy at no charge within three business days.⁸

The price you see every day is the fund’s net asset value: total assets minus liabilities, divided by the number of shares outstanding. For mutual funds, NAV is calculated after the market closes and sets the price at which shares are bought and redeemed that day.²

The Protections Built Around Your Money

Every investment company operating in the United States must register with the Securities and Exchange Commission under the Investment Company Act of 1940. The Act imposes disclosure requirements, governance rules, and restrictions on transactions between funds and their affiliated parties.⁹

A qualified custodian, typically a bank or registered broker-dealer, holds the fund’s actual securities and cash. This separation is deliberate: the people making investment decisions never have physical control of the assets, which protects investors from misappropriation.¹⁰ Fund accountants independently track expenses and reconcile the company’s records against what the custodian actually holds. A separate transfer agent maintains the shareholder registry and makes sure distributions reach the right people.

Governance adds another check. At least 40% of a fund’s board of directors must be people who are not affiliated with the investment adviser, and when the fund’s principal underwriter is connected to the adviser, a majority must be independent.¹¹ Funds that want to rely on certain SEC exemptions must go further, with at least 75% independent directors.¹² These independent directors approve the advisory contract, review fees, and watch for conflicts of interest.

The enforcement side has teeth. Willful violations of the Act or materially misleading statements in required filings carry criminal penalties of up to $10,000 in fines, up to five years in prison, or both, along with civil penalties the SEC can seek in court.¹³ The whole structure is layered and expensive to run, and it exists because the industry manages trillions of dollars belonging to ordinary people who are trusting someone else to handle their money honestly.

1
U.S. Securities and Exchange Commission. Registered Investment Companies Statistics
2
Investor.gov. Mutual Funds and Exchange-Traded Funds – A Guide for Investors
3
Investment Company Institute. A Guide to Closed-End Funds
4
Office of the Law Revision Counsel. 15 U.S. Code 80a-26 – Unit Investment Trusts
5
FINRA. FINRA Rule 2341 – Investment Company Securities
6
Office of the Law Revision Counsel. 26 USC Subchapter M, Part I – Regulated Investment Companies
7
Internal Revenue Service. Instructions for Form 1099-DIV
8
eCFR. 17 CFR 270.30e-3 – Internet Availability of Reports to Shareholders
9
Office of the Law Revision Counsel. 15 U.S. Code 80a-3 – Definition of Investment Company
10
U.S. Securities and Exchange Commission. Final Rule – Custody of Funds or Securities of Clients by Investment Advisers
11
Office of the Law Revision Counsel. 15 U.S. Code 80a-10 – Affiliations or Interest of Directors, Officers, and Employees
12
eCFR. 17 CFR 270.0-1 – Definition of Terms Used in This Part
13
Office of the Law Revision Counsel. 15 U.S. Code 80a-48 – Penalties