How to read a variable rate: APY, as-of times, drivers

A yield product shows a rate, and for the products covered in these guides that rate is variable. That one word changes how the number should be read: it is a snapshot of conditions at one moment, not a term that was agreed in advance.

This guide explains what a variable rate is, how APY differs from a plain interest rate, what an "as of" time tells you, what moves a rate, and why two screens can show different numbers for the same product. It shows no rate numbers on purpose, because a number can be out of date as soon as conditions move. For where the yield comes from in the first place, start with where stablecoin yield comes from or the stablecoin yield topic page.

What does "variable rate" mean?

A variable rate is a rate that can change over time, so the number on a screen is a reading taken at one moment, not a fixed term. Providers use the word, or something close to it, in their own documentation.

• Jupiter describes Lend rates as "Variable. Adjusted automatically based on supply and demand."
• Aave's documentation says "Interest rates adjust with utilization" (Aave V3 overview).
• Maple states that "the yield rate may vary and could be zero or negative in adverse market conditions" and that yields are not assured (risk disclosures).

Three providers with three different mechanisms reach the same practical point: the rate moves. A reading says what the rate was when it was taken. It does not say what the rate will be tomorrow, and no one promises a rate.

What is the difference between APY and APR?

In US deposit-account rules, APY reflects compounding and a plain interest rate does not, while crypto screens apply the labels APY and APR less consistently. The rule is Regulation DD, which defines APY as a rate reflecting the total amount of interest paid on an account, based on the interest rate and the frequency of compounding. It defines the interest rate as the annual rate of interest paid on an account, and says that it does not reflect compounding. The FDIC's examination manual covers the same definitions.

Compounding is simple to describe without any numbers. The Consumer Financial Protection Bureau explains that compound interest is "when you earn interest on the money you've saved and on the interest you earn along the way", and that a higher compounding frequency makes savings grow faster.

A worked example, with no figures, shows the idea. Suppose interest is credited to a balance every day. On day one, interest is earned on the starting balance. On day two, interest is earned on the starting balance plus day one's interest. Repeat that for a year and the balance has grown by more than interest on the starting balance alone would give. APY includes that extra growth. A rate that does not reflect compounding leaves it out. The more often interest is added to the balance, the larger the gap between the two.

On crypto and DeFi screens the labels are applied less consistently. A figure can be called APY, APR or just "rate", and the label alone does not settle whether compounding is included. Jupiter's developer documentation, for example, tracks yield without rewards and with rewards separately. The table sets the terms side by side.

The takeaway is a reading habit: find the product's own definition of the figure before comparing it with another one.

What does an "as of" time tell you?

An "as of" time tells you when the rate was read, which is how a variable rate is placed in time. A rate with no time attached could be from this minute or from last month, and the two readings may be far apart.

The older a reading is, the less it says about the present. That is true of any variable figure. It is also why the time should come from the source of the rate, not from the moment a page was opened.

In Neovestor, every Earn rate is labeled variable and carries an "as of" time taken from the source. Rate sources are refreshed about every five minutes, and a rate older than six hours shows "Rate update delayed". The message is a signal that the number on screen is no longer a recent reading.

What moves a variable rate?

The activity that generates the yield moves the rate. For lending products that means how much of a pool is borrowed and how much demand there is. For loan-based products it also means how borrowers perform and what markets are doing.

One more detail explains why the rate a depositor sees can differ from what borrowers pay. In a pooled lending protocol, Aave notes that "Supplier yields are funded by borrower interest net of the reserve factor". The depositor's figure is what remains after that deduction, not the full interest borrowers pay.

Aave's introduction describes the direction of the effect: when a large portion of the pool is borrowed, the interest rate increases, and when most of the pool is idle, it decreases. Aave is cited as a general example of how pooled lending works. It is not a Neovestor partner.

How does a rate show up in a balance?

It depends on the product: the same yield can appear as a rising price per token or as a growing number of tokens. Ondo's documentation shows both patterns within one product family. USDY is an accumulating token whose price per token rises as yield accrues. The separate rebasing token, rUSDY, keeps a price of $1.00 and adds tokens instead.

That difference matters when reading a screen. A balance shown as a token count, a balance shown in dollars and a price chart can each move for different reasons. Before concluding that a rate is not showing up, check which of these a product uses to show its yield.

Why do two screens show different numbers for the same product?

Because the label, the inclusion of compounding or rewards, and the "as of" time can all differ between screens. Any one of the three is enough to produce two different figures for the same product on the same day.

• Different labels. One screen shows APY and another shows APR or "rate". The two are defined differently in US deposit-account rules, and crypto screens do not always follow those definitions.
• Rewards in or out. One screen shows yield without rewards, another with rewards. Jupiter's developer docs track the two separately.
• Different times. One reading was taken this morning and the other this evening. Because the rate is variable, both can be accurate for their own moment.

A reader who sees two numbers can usually resolve the difference by checking those three points in order. If they still differ, the provider's own page is the reference, since the provider defines what its figure includes.

How can a rate be read on any screen?

Check five things in order, starting with the label and ending with the provider's risk disclosures. The same sequence works for any yield product in any app.

1. The label. Is the figure called APY, APR or just "rate"? Look for the product's own definition.
2. Compounding and rewards. Does the figure include compounding? Does it include rewards, or exclude them?
3. The "as of" time. When was the rate read, and by whom? A time that comes from the source is more informative than the time the page loaded.
4. The source of the yield. Is it borrowers paying interest in a pool, short-term Treasuries, or loans to institutions? The guide to where stablecoin yield comes from describes each source and the risk that comes with it.
5. The provider and its disclosures. Who runs the product, what risks does the provider list, and how do withdrawals work? Jupiter and Maple, for example, both document how withdrawals can be limited or queued.

Two rates should only be compared when the label, the compounding, the rewards and the time all match. Even then, a rate is one input. The activity behind it, such as lending, Treasury-linked notes or institutional loans, carries a different kind of risk, and a rate does not show which.

Apps that give a dollar account built on stablecoins, covered in what a stablecoin neobank is, sometimes include earning among their features. The same five checks apply there, because the label and the "as of" time belong to the figure, not to the app that displays it.