Retirement Portfolio Diversification: Asset Classes, Tax Buckets, and Age 

What is retirement portfolio diversification?

Retirement portfolio diversification means spreading your retirement savings across different kinds of investments, account types, and sources of return, so that no single market, asset, or tax rule decides your outcome. It lowers the odds that one bad stretch does outsized damage. It does not remove risk or guarantee a result. 

The idea is simple: don't put all your eggs in one basket. The SEC's Office of Investor Education describes diversification as spreading money among different investments to reduce risk, and notes that conditions that hurt one asset class may help another (Investor.gov). In retirement, four questions shape how that plays out: 

1. What job does each asset do: growth, income, or stability? 

2. How will each account be taxed when you use the money? 

3. How long until you need it? 

4. How much sits in public markets versus alternatives? 

This guide takes them in turn. If you would rather start with your own numbers, the retirement diversification calculator sorts your holdings into these categories. 

Why diversification matters more once you start withdrawing 

Concentration is quiet. A portfolio can hold many funds across several accounts and still lean on one market. The SEC points out that a mutual fund or ETF won't necessarily diversify your portfolio, especially a narrowly focused one, and suggests checking the top holdings of each fund you own to confirm they differ (Investor.gov). 

Recent history shows why stocks and bonds alone are not always enough. In 2022 the S&P 500 fell 18.1% and the Bloomberg U.S. Aggregate Bond Index fell 13.0%, the index's worst year by a wide margin. A Callan review prepared for the Arkansas Judicial Retirement System notes that stocks and bonds have fallen together in about 10% of quarters over nearly a century, but on an annual basis only twice. 

The same report shows how differently other assets behaved that year: 

Two lessons follow. Some assets did behave differently from stocks and bonds. But "real estate" is not one behavior: listed REITs fell harder than the stock market, while private real estate indexes, which rely on appraisals that can smooth reported swings, held up. Past performance does not predict future results. 

Diversification also matters more once you are withdrawing. When spending comes out of the portfolio, a downturn can force sales at lower prices. Holdings that behave differently give you more choices about what to sell, and when. 

Diversify by asset class: growth, income, and stability 

The simplest way to see your mix is by the job each holding does. This is also how the worksheet sorts your portfolio. 

The SEC says the right allocation is personal and shifts with your time horizon and risk tolerance. No table can pick it for you. 

Diversify within each role, not only between them. Stocks can differ by region, company size, and sector. Bonds can differ by maturity, credit quality, and issuer. The 2022 results show why. In that year the same Callan report shows long-term government and credit bonds fell 27.1%, intermediate ones fell 8.2%, and short-term ones (one to three years) fell 3.7%. All were "bonds." They did not behave alike. 

A fund is not a role. Funds make it easy to own many holdings at once, and broad ETFs are one way investors do that. But three large U.S. stock funds can hold many of the same companies. Check the top holdings of each fund to see whether you own three different things or one thing three times. 

Tax diversification in retirement: pre-tax, Roth, and taxable 

Asset classes are one half of the picture. The other half is when each account is taxed. Money held in different tax buckets gives you more than one lever to pull when you start taking withdrawals. 

The IRS says you generally must start withdrawals from traditional IRAs, SEP IRAs, SIMPLE IRAs, and 401(k) plans at age 73, and that required withdrawals are not imposed on Roth IRAs or designated Roth accounts while the owner is alive. Missing a required withdrawal can trigger a 25% excise tax on the shortfall, or 10% if corrected within two years. The age is scheduled to rise for later birth years, so check the IRS page for your own situation. The IRS also explains that Roth IRA qualified distributions are tax-free when requirements are met. 

Why it matters for diversification. A portfolio with most of its value in pre-tax accounts has a large amount of future taxable income already scheduled. Money in Roth or taxable accounts gives you more choices about which account to draw from in a given year. Tax rules change, and the right mix depends on your income, state, and plans, so a tax professional is the right person to model it. 

A self-directed account is not a fourth bucket. A self-directed IRA is a traditional or Roth IRA held by a custodian that allows a broader range of assets. The tax treatment follows the IRA type. What changes is what you can hold. Retired.com offers self-directed IRAs, plus Solo 401(k) and SEP IRA options for self-employed savers. 

Retirement diversification by age: how the mix shifts over time

Time horizon is one of the main factors the SEC says should shape your allocation, along with risk tolerance. The longer until you need the money, the more room you have to ride out declines. The closer you get, the more a bad stretch can disrupt spending. 

For a real-world picture of that shift, look at the federal government's Thrift Savings Plan (TSP), the retirement plan for federal employees and military members. Its lifecycle funds follow a published glide path. This is one plan's design, not a recommendation for your portfolio. 

Source: FRTIB 2024 L Funds Asset Allocation Review, allocations as of July 2024, rounded. TSP allocations adjust over time, so check tsp.gov for current figures before publishing. 

Three patterns stand out: 

• Decades out, growth leads. There is time to recover from declines, and future contributions buy more shares when prices are low. 

• The last ten years or so, stability builds. Shifting toward bonds and government securities means near-term spending is less likely to depend on selling stocks in a downturn. 

• In retirement, all three roles stay. The review modeled a 35-year retirement horizon, so even the most conservative TSP fund keeps about a quarter in stocks. 

The review's consultant also found that the overall risk level mattered more to outcomes than the exact shape of the glide path. Higher stock allocations produced better expected results but worse results in the downside cases. 

Your mix may differ, for good reasons. TSP's glide path assumes participants also have a federal pension and Social Security. Your other income, health, home equity, and spending needs all change what is right for you. To see where you stand today, run your holdings through the diversification worksheet and check your overall readiness with the Retirement Score. 

Where alternative assets fit in a retirement portfolio 

Alternative assets are investments outside the traditional mix of public stocks, bonds, and cash. Common examples are real estate, precious metals, crypto, and private investments. They are the fourth question from the start of this guide, and the one most guides skip. 

Why large institutions hold them. Yale's endowment is the best-known example. For fiscal 2020 it targeted just 2.75% in U.S. stocks, with most of the rest in absolute return strategies, venture capital, buyouts, real estate, and natural resources, according to a Yale announcement. Two details matter for individual savers. 

• Yale has a different job. Its endowment is built to support the university in perpetuity, with a professional staff and no need to sell in a hurry. A retiree needs spending money on a schedule. 

• Yale still sets guardrails. It targets at least 30% in market-insensitive assets (cash, bonds, absolute return) and seeks to cap illiquid assets at 50%. Its 10-year return through mid-2019 was 11.1% a year, behind U.S. stocks at 14.7% and ahead of bonds at 3.9%. Diversification is not a promise to beat the stock market. 

What individual savers should weigh. A joint investor alert from NASAA, the SEC's investor education office, and FINRA lays out the risks of holding alternatives in a self-directed IRA: 

• Limited information and liquidity. Private investments may disclose little, financial statements may be unaudited, and selling can be slow or restricted, including when you retire or must take required withdrawals. 

• Hard-to-verify values. Statements may show the purchase price or a figure supplied by the promoter. The alert suggests independent valuation where possible. 

• Complex tax rules. Self-directed IRAs must follow IRS rules, including those on prohibited transactions. Breaking them can cost you the account's tax-deferred status. 

• Higher fees. Account, transaction, and asset-specific fees can exceed those on standard accounts. 

• Fraud. Custodians do not evaluate whether an investment is legitimate, and using a legitimate custodian does not make an investment legitimate. 

• Crypto specifics. Some crypto assets may be securities offered without SEC registration, and platforms that call themselves exchanges may not be registered. 

How to think about size. There is no single right percentage. A practical test is whether you could cover spending and required withdrawals from liquid holdings if your alternatives could not be sold for years. Decide how you would exit before you buy. 

If you want to explore the options, start with our alternative assets overview. Related guides cover the self-directed IRA, the Checkbook IRA, real estate IRAs, precious metals IRAs, and crypto IRAs. Neither the IRS nor any other government body approves or endorses any investment held in an IRA. 

How many retirement accounts do you need to diversify? 

There is no magic number. Diversification comes from what the accounts hold and how they are taxed, not from how many you have. Each extra account adds a place where holdings can overlap and a statement to track. A useful rule: every account should have a reason to exist, either a tax bucket or a role in the mix. 

These are examples, not recommended structures. Whatever you choose, add up holdings across every account. The SEC's advice to check fund top holdings applies across accounts too. The same funds can sit in three places. 

A diversified portfolio example 

Abstract advice only goes so far, so here is a concrete mix. The first column is the TSP's age-47 allocation from the glide path above, shown by the five funds it uses. The second column is simple arithmetic: it shrinks each holding by one-tenth to make room for a 10% alternatives sleeve. The 10% is an illustration of the math, not a target. 

Example 1 is from the FRTIB 2024 L Funds Asset Allocation Review, L 2040 fund, July 2024, rounded. Hypothetical, not a recommendation. 

Both examples spread risk across regions, company sizes, and bond types. Example 2 adds a holding that may behave differently from all of them, along with the liquidity, valuation, and fee questions covered above. Whether either fits depends on your goals, timeline, and other income. 

Common diversification mistakes

• Counting funds instead of exposures. Several funds with the same top holdings are one bet, not several. 

• Letting winners run unchecked. The SEC gives the example of a 60% stock allocation drifting to 80% after strong gains, which changes your risk without any decision on your part.

• Ignoring tax buckets. Money concentrated in pre-tax accounts means required, taxable withdrawals beginning at 73. 

• Holding what you cannot sell. Illiquid alternatives can be a problem when you need cash or must take required withdrawals. 

• Rebalancing constantly. The SEC notes that rebalancing tends to work best when done relatively infrequently, with some experts suggesting every six or 12 months. 

• Treating an example as advice. Glide paths and sample mixes show a pattern. They do not know your situation. 

How to check your own mix 

You can do this in four steps, with a pencil or with the retirement diversification calculator, which groups your holdings by growth, income, stability, public markets, and alternatives. 

1. List every account and what it holds, including old employer plans. 

2. Sort holdings by role and type: growth, income, stability, and public versus alternative. 

3. Check overlap by looking at the top holdings of each fund. 

4. Note each account's tax bucket and when required withdrawals begin. 

Then compare what you find with your goals and time horizon, and consider talking it through with a qualified professional. 

See how diverse your portfolio is today 

Run your holdings through the retirement diversification calculator to see your mix by role and by public versus alternative assets, then come back to this guide to interpret what you find. 

Frequently Asked Portfolio Diversification Questions

This article is educational and general in nature. It is not legal, tax, investment, or other professional advice. Investing involves risk, including possible loss of principal. Past performance does not guarantee future results. Neither the IRS nor any governmental or regulatory authority has approved or endorsed any investment available through Retired.com. 

Sources 

• IRS, Retirement topics: Required minimum distributions 

• IRS, Roth IRAs 

• SEC Office of Investor Education, Asset Allocation and Diversification 

• NASAA, SEC OIEA, and FINRA, Investor Alert: Self-Directed IRAs and the Risk of Fraud (February 7, 2023) 

• Callan, Fourth Quarter 2022 Executive Summary for the Arkansas Judicial Retirement System 

• Federal Retirement Thrift Investment Board, 2024 L Funds Asset Allocation Review (May 2024) 

• Yale News, Investment return of 5.7% brings Yale endowment value to $30.3 billion (September 27, 2019) 

• Yale News, Yale reports investment return for fiscal 2025 (October 24, 2025)