WhitmanTrading

Certificates of Deposit

A certificate of deposit is a bank deposit paying a fixed rate for a fixed term, usually with a penalty for early withdrawal. The rate is locked at the start, which removes reinvestment risk for the term and removes your access to the money at the same time.

You give a bank money for a fixed period and it pays a fixed rate. The simplicity is the appeal, and the two things worth reading are what happens if you need the money early and how it compares to the government alternative.

How it works

A candlestick chart with a fixed level held across a defined period.
A fixed rate for a fixed term. Illustrative chart - not real market data.

You deposit an amount for a stated term and receive a stated rate. Terms run from a few months to several years and the rate is generally fixed for the whole period.

The first half of a price series with an unchanging baseline.
The rate does not move once it is set. Illustrative chart - not real market data.

Nothing changes it afterwards. If prevailing rates rise, you keep the old one; if they fall, you keep the old one. That symmetry is the product.

A section of the price series with an early exit penalised.
And early access generally costs something. Illustrative chart - not real market data.

Early withdrawal usually forfeits some interest. The size of that penalty varies enormously between institutions and terms, and it is the single most useful thing to check before depositing.

A worked example

A window of price bars over a defined term.
A fixed rate compounding over a fixed period. Illustrative chart - not real market data.

Take 20,000 deposited for two years at 4.5%, compounded annually.

After one year it is 20,900.

After two it is 21,840.50, so the total interest is 1,840.50.

Now withdraw after fourteen months with a six-month interest penalty. Six months of interest at that rate is roughly 450, which comes off whatever had accrued — turning a good rate into a mediocre one for the period actually held.

Against the alternatives

The second half of a price series with two comparable holdings.
Two similar-looking products with different mechanics. Illustrative chart - not real market data.

Against a savings account, this trades access for a fixed rate. A savings rate can be cut the week after you deposit; this one cannot.

Against a Treasury bill, the differences are tax and exit. A bill can be sold at market price with no penalty, and in several jurisdictions government interest carries a state or local tax exemption a bank deposit does not.

Against a money market fund, this fixes the rate where the fund floats it. The fund is more accessible and the deposit is more predictable, and which is better depends entirely on whether rates are about to fall.

Deposit protection

A candlestick series with a protected floor beneath it.
A deposit is protected in a way a fund is not. Illustrative chart - not real market data.

This is a bank deposit, so a deposit protection scheme generally covers it up to a per-institution limit, which is a genuine difference from a money market fund.

The limit is per institution rather than per account, so spreading a large sum across several banks is the standard response — and worth doing before rather than after.

The ladder

A long-horizon candlestick view with staggered maturities.
Staggered terms restore some access. Illustrative chart - not real market data.

Splitting the money across several terms means one matures regularly. A five-rung ladder with a maturity each year gives annual access without a penalty, while most of the money stays on longer terms at better rates.

It also averages the reinvestment rate rather than committing everything at one moment, which is the same argument the treasury bill page makes about rolling short instruments.

Costs and tax

A candlestick chart annotated with the round-trip cost of a switch.
There is no spread, and there is a penalty. Illustrative chart - not real market data.

There is no spread and no commission. On this site’s shared series a round trip in a traded security measures about 2% of the median bar range of 0.493, and none of that applies here — the cost is entirely the early-withdrawal penalty.

Price bars with maturities planned in advance.
And the interest is taxable as it is credited. Illustrative chart - not real market data.

Interest is generally taxed as ordinary income in the year credited, even on a multi-year deposit where nothing has been paid out yet. This is educational, not tax advice, and treatment varies.

What to check before depositing

The penalty, expressed in months of interest. Six months on a one-year deposit is severe; ninety days on a five-year one is mild. The two are described with the same words and are not the same product.

Whether the rate is fixed or promotional. Some accounts pay a headline rate for an introductory period and revert, which is a different thing from a fixed term.

How it matures. Automatic renewal into whatever rate applies on that day is a common default, and a deposit that rolls over unnoticed can sit at a poor rate for another full term.

And whether the institution is covered. Protection is per authorised institution, and two brands can share one licence — in which case the limit covers both together rather than each.

The original data

Of the 24,971 unique videos in research/search-study-corpus.jsonl, zero have a title about certificates of deposit. Treasury bills and money market funds also return zero, while bonds appear in 2 videos at a median of 87,102 views. The counts come from site/rank_investing.py, which deduplicates by video id.

A candlestick series with several gaps, the largest of them marked.
A rate move affects the next deposit, not this one. Illustrative chart - not real market data.

Zero videos across the entire fixed-rate savings category. Every cash instrument on this site returns nothing from the corpus, which is a consistent finding rather than a gap in any one subject: this is a trading corpus, and cash is where money waits.

A stretch of price bars cut short at a decision point.
Rates look high. Lock in for five years? Illustrative chart - not real market data.

The answer to the question on that chart is that locking in is a view about rates and losing access is the price of it. If the money is genuinely not needed for five years, fixing the rate removes five reinvestment decisions. If the horizon is uncertain, the penalty is the thing that bites — and a ladder gets most of the rate with most of the access.

When it fails

The failure is a long deposit made with money that turns out to be needed. A five-year term at an attractive rate looks like prudence right up until a roof, a job change or a family obligation arrives in year two, and the penalty converts a careful decision into a worse outcome than a plain savings account would have produced. The rate was never the problem; the horizon was estimated optimistically and there was no mechanism to correct it.

The second failure is not reading the penalty. It varies enormously and it is the whole risk.

A third is exceeding the protection limit at one institution. The limit is per bank.

A fourth is comparing headline rates before tax. Government interest may be treated differently.

A fifth is forgetting the interest is taxable as credited. A multi-year deposit can produce a bill before it pays out.

And a sixth is using it for an emergency reserve. A reserve you are penalised for using is not one.

Treasury bills is the government version with different tax and no penalty. Money market funds is the floating-rate alternative. And emergency fund is the job this product is often wrongly given.

What I actually do

The comparison worth doing is against a short government bill rather than against a savings account. Both lock a rate, both are very safe in different ways, and the differences that decide it are the tax treatment and whether you can get the money back — not the headline rate, which is usually close.

— Michael Whitman

This page is educational, not financial advice. Test every idea on your own charts before risking money.