Designing the cadence: monthly, quarterly or annual rungs

Which of these are you?

• You spend from the ladder every month: use monthly rungs of one month of spending each, built by opening a 12-month CD on the same day each month. It is the most work and the least yield.
• You refill a savings account a few times a year: use quarterly rungs. Each rung covers three months of spending and you make four decisions a year.
• You hold the money as a long-term reserve and spend it rarely: use annual rungs, as in the ladder blueprint. It is the least work and pays the most when longer terms pay more.
• You have bills due on fixed dates, such as estimated taxes or tuition: size each rung backward from the bill and let the calendar set the spacing.

How do you choose the spacing?

Choose the spacing from your cash needs, not from a rule of thumb. The shorter the gap between maturities, the sooner cash arrives and the shorter the average remaining maturity, which on a rising curve means a lower yield and more accounts to manage.

The three common cadences, held in steady state with $60,000, look like this. The table splits the $60,000 evenly across rungs, so the rung sizes are capital divided by N. The sizing formula in the next section sizes rungs to spending instead, which is why $4,000 a month gives $12,000 quarterly rungs there and $15,000 here. The CD term column is the length of each CD; the average remaining maturity column is the mean time left across the ladder's CDs. The rates come from a hypothetical curve chosen for round numbers: 4.15% for 12 months, 4.45% for 60 months. They are not current quotes and not a forecast. Monthly and quarterly ladders are built from the same 12-month term opened on staggered dates. The annual ladder is five rungs rolled into 5-year CDs, as in Chapter 6.

The ladder's average remaining maturity in steady state is the spacing s times (N + 1) / 2, in months. For the monthly ladder, s is 1 and N is 12, so 1 x 13 / 2 = 6.5 months. For quarterly, 3 x 5 / 2 = 7.5 months. For annual, 12 x 6 / 2 = 36 months. In each case the remaining maturities run from s months up to N x s months.

The yield price of frequency is the gap between the last two rows: $2,670 minus $2,490 is $180 a year, or 0.30 percentage points on $60,000. That gap exists only because the hypothetical curve rises with term. On a flat curve it is close to zero and on an inverted curve the short ladder wins, which is why you should compare rates by term on the day you build.

A monthly and a quarterly ladder earn the same blended rate here because both use one 12-month term. What monthly buys you is smaller, more frequent events. What it costs is eight more accounts and eight more decisions a year.

How do you size rungs to your spending?

Rung size equals monthly essential spending times the months between maturities. Ladder capital equals that rung size times the number of rungs, and it funds spending for spacing times N months. At $4,000 a month on a quarterly ladder, each rung is $12,000 and four rungs fund 12 months.

Write it as: rung size = B x s, capital = B x s x N, coverage = s x N months, where B is monthly spending and s is the months between maturities. With B = $4,000, s = 3 and N = 4: rung = $12,000, capital = $48,000, coverage = 12 months. A monthly ladder for the same spending has rung = $4,000 x 1 = $4,000 and 12 rungs.

The formula gives the dollars you need at each maturity. You do not deposit that amount, because interest does part of the work. To fund $12,000 at month 3, $12,000 at month 6, $12,000 at month 9 and $12,000 at month 12, deposit the present value of each: need divided by (1 + APY) raised to the term in years. Using the hypothetical APYs of 4.00, 4.05, 4.10 and 4.15 percent:

The four deposits total $46,812.66, so interest supplies the remaining $1,187.34 of the $48,000 spending need. Check rung 2 by hand: 12,000 / 1.0405^0.5 = 12,000 / 1.02005 = $11,764.14.

This spending-down ladder has a tier mix. Its 3- and 6-month rungs are due inside 180 days, so they are funded from Tier 2 vehicles; the 9- and 12-month rungs are Tier 3, which covers dated goals 181 to 720 days out. Rungs of 60 months, such as the annual ladder above, are longer-horizon money outside the cash tiers, only for cash you will not need before it matures. The reserve that covers emergencies stays in Tier 2, and the operating cash for the month stays in Tier 1. Where the ladder pays out into a savings account, that account is the buffer that absorbs a late maturity or a surprise.

How do you match rungs to bills with fixed dates?

Set each rung's term from the number of days to the bill, and size it backward from the amount due. Choose a maturity a few business days before the due date so the money can move, because the bill date does not wait for a bank transfer.

Federal estimated income tax is a clear example. The IRS divides the year into four payment periods, with payments due April 15, June 15, September 15 and January 15 of the following year. If the date falls on a Saturday, Sunday or legal holiday, the payment is on time the next business day. The IRS says individuals generally must make estimated payments if they expect to owe $1,000 or more when they file.

The gaps between those dates are not equal. Counted in a non-leap sequence, April 15 to June 15 is 61 days, June 15 to September 15 is 92 days, September 15 to January 15 is 122 days, and January 15 to April 15 is 90 days. A calendar-quarterly ladder with maturities exactly three months apart misses the third and fourth due dates by weeks. The fix is to set each rung's term from days, not from a round number of months, and to size it to that bill.

A worked case: a $6,000 payment due six months from today. A 6-month CD at a hypothetical 4.05% APY needs a deposit of $6,000 / 1.0405^0.5 = $5,882.07 today. Depositing the full $6,000 would tie up $117.93 more than the bill needs. The interest you earn on the CD is itself taxable income, so if you are close to a threshold, remember the interest raises what you owe. Our phantom income guide covers when CD interest is taxed.

Tuition, property tax and insurance premiums work the same way: the due date sets the term and the amount due sets the rung.

How do you build a monthly or quarterly ladder from standard terms?

Open the same term, commonly 12 months, on the same day each month for a monthly ladder, or each quarter for a quarterly one. After N deposits the ladder is in steady state and one CD matures every s months. The build takes N x s months, less one gap.

This staggered-start method needs no unusual terms. You do not need a 5-month or 7-month CD. You need one deposit and one calendar entry each month. The cost is that money waits its turn in savings. On $60,000 split into 12 monthly deposits of $5,000, tranche k waits k - 1 months before it is deposited. If the waiting money earns 0.40 percentage points less than the CD, the drag is $5,000 x 0.40% x (0 + 1 + ... + 11) / 12 = $5,000 x 0.004 x 66 / 12 = $110.00. This is a simple-interest approximation of the shortfall between the CD rate and the savings rate the waiting money earns.

If you already hold the whole $60,000 in cash, you have a choice: deposit it all at once into a mixed-term ladder and accept a lower average yield for the first year, or stagger it and accept about $110 of drag. If your cash arrives monthly from income, staggering costs nothing, because there is no waiting balance.

Standard-term ladders can also be built at once by buying terms the bank lists. If your bank offers 3, 6, 9 and 12 month terms, one purchase of each gives a quarterly ladder immediately. Check your bank's actual term list before you plan around any specific terms.

The calculator's defaults reproduce the quarterly build: $15,000 per rung, terms of 3, 6, 9 and 12 months, and a blended 4.075% on the hypothetical curve. Replace the APYs with the rates you are quoted for each term.

What do more rungs cost?

Each extra rung adds an account, a maturity date, a notice and a decision. It also shrinks each rung, which can push it below a bank's minimum deposit. The maximum number of rungs is the total divided by the smallest minimum, rounded down.

The three costs in practice:

• Accounts and dates. Twelve rungs means 12 maturity dates and 12 renewal notices a year. Federal rules require a notice before maturity for auto-renewing CDs longer than one month, at least 30 calendar days ahead or at least 20 days before the end of a grace period of at least five days (12 CFR 1030.5(b)).- Minimum deposits. The maximum rung count is capital divided by the minimum deposit, rounded down. With $60,000 and a $10,000 minimum, N can be at most 6. With a $2,500 minimum it is 24, and with $1,000 it is 60. Minimums vary by bank and by term, so check each product.
• Insurance. All the rungs at one bank share one FDIC limit per ownership category, and accrued interest counts toward it. Twelve CDs at one bank do not create twelve limits. See Chapter 4.

A useful rule: add rungs only until each event is small enough to be a routine decision, and stop before the calendar becomes a job.

How should you review the cadence?

Review it when your spending changes or a rung matures, not on a fixed date. Recompute rung size from current monthly spending, and if a rung is now larger than a month or a quarter of spending, consider whether that money belongs in Tier 3 at all.

At each maturity, ask three questions in this order. Do I need this cash for spending in the next spacing interval? If not, does this rung still belong at the longest term on the ladder? And does the current spacing still match how I spend? Chapter 8 walks through the maturity decision, including the notice, the grace period and the rollover default.