Assumptions

App default — set by the app's creator, no live data source. Edit if you have a different view.

An extra sliver of slippage that hits ONLY the AMM liquidity-pool strategy when you join it. To supply an XRP/RLUSD pool you need equal dollar amounts of BOTH tokens, so the protocol takes your dollars and spends half of them buying XRP. That half-purchase nudges the price slightly against you — a small extra cost on top of the ordinary entry slippage. ('Slippage' = the gap between the price you saw and the price you got.) Measured in basis points (bps): 1 bps = 0.01%. Charged once, at deployment.

Formula: AMM LP pool value at month 0 = capital × (1 − (entryBps + halfBuyBps) ÷ 10,000)

Compounding: Applied once at deployment; does not compound across the horizon.

App default — set by the app's creator, no live data source. Edit if you have a different view.

A one-time fee charged when a strategy has to 'bridge' your XRP onto another blockchain to earn its yield — today that's the Flare-Firelight strategy, which moves XRP over to the Flare network. (Bridging means locking up your real XRP and minting a stand-in token on the other chain.) It's charged once, at the moment you deploy, and measured in basis points (bps): 1 bps = 0.01%, so 10 bps on a $10,000 deposit is about $10. It stacks on top of entry slippage, so the full cost of getting started is entry + bridge.

Formula: Flare-Firelight starting balance = capital × (1 − (entryBps + bridgeBps) ÷ 10,000) ÷ XRP price

Compounding: Applied once at deployment; does not compound across the horizon.

App default — set by the app's creator, no live data source. Edit if you have a different view.

A 'CEX' is a Centralized Exchange — a company like Binance, Kraken, Coinbase, or Bitrue where you buy and hold crypto in an account THEY control. Their 'Earn' products pay you a yearly rate (APR = Annual Percentage Rate) in exchange for letting them put your XRP to work. Realistic range is about 1.5–8%. 'Flexible' products you can withdraw anytime pay the least (roughly 1.5–2%); 'fixed-term' products that lock your XRP up for a set period pay a bit more (3–5%); and limited-time promotions can reach 8% or higher. Whatever rate you set, the chart grows your XRP balance at it month by month.

Formula: XRP balance next month = XRP balance × (1 + (APR ÷ 12) × (1 − tax rate)) (tax rate is the Global federal-tax assumption)

Compounding: Monthly on the XRP balance — yield accrues in XRP, not USD.

App default — set by the app's creator, no live data source. Edit if you have a different view.

'LGD' (Loss-Given-Default) is the fraction of your money you'd lose for good if the exchange went bankrupt. It's high here for a structural reason: when you use a centralized exchange, IT holds your crypto, and many exchanges quietly lend it out or reuse it behind the scenes (the jargon is 'rehypothecation') instead of keeping it set aside for you in a 'segregated' account that's legally yours. If the exchange fails, you become just another creditor in its bankruptcy and recover only what the courts can claw back. History sets the range: Celsius depositors recovered roughly 50–60%, Voyager about 35%, BlockFi about 40%, FTX 70%+. A 65% LGD means you'd expect to lose about 65 cents on the dollar and recover the other 35.

Formula: net loss = default magnitude × loss-given-default × current XRP balance (computed per IssuerDefault event)

The headline yield 'earnXRP' advertises — the big number on the marketing page. earnXRP stands in for any 'opaque wrapper': a product that promises a yield but won't fully show you what it's doing with your money behind the scenes. Because you can't see the risks you're taking, this claimed number on its own does NOT drive your chart. The chart uses this figure minus a 'risk-premium drag' (the next knob), which discounts the promise to reflect those hidden risks. Looking ahead: regulated, traditional-finance institutions are beginning to offer a tamer cousin of this — they custody your crypto for you, spread it across several yield sources, and pay you a regular distribution, taking a management fee in return. The trade is usually lower risk and far less learning curve in exchange for a slightly smaller net yield. There's no separate line for that on the chart yet (it would behave much like this one), but you can model it right here: set a modest claimed yield and treat the drag as the management fee rather than as hidden risk.

Formula: (not directly applied — see effective APR below)

App default — set by the app's creator, no live data source. Edit if you have a different view.

How much to shave off earnXRP's advertised yield to account for the risks it hides. Because earnXRP won't show you exactly what it does with your money, its realistic expected return is lower than the headline once you price in the chance of a bridge being hacked, a smart-contract bug, sloppy execution, or the custodian losing your funds. Subtracting this 'drag' from the claimed rate gives the 'effective' (realistic) yield the chart actually draws. Example: a 10% claim minus a 4% drag becomes a 6% line.

Formula: effective APR = claimed APR − risk-premium drag · XRP balance next month = XRP balance × (1 + (effective APR ÷ 12) × (1 − tax rate))

Compounding: Subtracted from claimed APR; never exceeds claimed (strict invariant — engine throws).

App default — set by the app's creator, no live data source. Edit if you have a different view.

Adds realistic up-and-down price wiggle — traders call it 'chop' — on top of the scenario's smooth line, so the chart looks more like a real market and less like a tidy curve. The chop is copied from a real slice of XRP's past that you choose below; it is NOT a forecast of the future. With this on, the chart shows what riding out that kind of historical bumpiness would have looked like under your chosen scenario shape. Turn it off for the clean, smooth line.

App default — set by the app's creator, no live data source. Edit if you have a different view.

'Slippage' is the small loss you take the instant you buy into a position: the price you actually get is a hair worse than the price you saw, because the market moves slightly as your order fills. This knob sets that cost at the moment you deploy, when your dollars are first converted into the asset. It's measured in 'basis points' (bps), a finance unit where 1 bps = 0.01% (so 100 bps = 1%). At 5 bps, buying $10,000 of something costs you about $5. It applies to the strategies that have to buy a non-stable asset to get going — holding XRP, the XLS-66d broker, the AMM pool, Flare-Firelight, and earnXRP. The dollar-based strategies (savings, USDC lending, T-bills) don't buy anything volatile, so they ignore this.

Formula: starting position value = capital × (1 − entrySlippageBps ÷ 10,000) (per applicable strategy)

Compounding: Applied once at deployment; does not compound across the horizon.

App default — set by the app's creator, no live data source. Edit if you have a different view.

'Slippage' is the small loss you take when you trade, because the price you actually get is slightly worse than the one you saw. This knob would model that cost at the moment you SELL out of a position at the end of the run. In practice the simulator deliberately does NOT model selling — it shows what your position is worth while you still hold it, not what you'd pocket after cashing out. (Deciding when to sell is timing the market, which this tool stays out of on purpose; the Methodology section explains why.) So this setting is here for completeness and doesn't currently change your chart. It's measured in basis points (bps): 1 bps = 0.01%.

Formula: final-month value = pre-exit value × (1 − exitSlippageBps ÷ 10,000) (only when liquidation-value toggle is ON)

Compounding: Would apply once at the final month if disposal were modelled; today it is not, so it leaves your chart unchanged.

This strategy earns yield by moving your XRP onto a different blockchain called Flare and putting it to work there. Two steps, each with a piece of jargon. First you 'bridge' your XRP to Flare: bridging means locking up your real XRP and getting a matching stand-in token (here called FXRP) on the other chain. Then you 'stake' that FXRP into a service called Firelight, which hands back a yield-bearing token called stXRP. 'Staking' just means committing your tokens to help run a network in exchange for rewards. This APR (Annual Percentage Rate) is the yearly reward, paid in XRP terms — your XRP pile grows. The bridging step itself pays nothing; it's just the toll you cross to reach the yield. The catch: each extra step (the bridge, the staking service) is one more piece of software that could be hacked or break, which is why this carries more smart-contract risk than simply holding XRP in your own wallet.

Formula: XRP balance next month = XRP balance × (1 + (APR ÷ 12) × (1 − tax rate)) (tax rate is the Global federal-tax assumption)

Compounding: Monthly on the XRP balance — yield accrues in XRP, not USD.

App default — set by the app's creator, no live data source. Edit if you have a different view.

APR stands for Annual Percentage Rate — the yearly interest a high-yield savings account (HYSA for short) pays you just for keeping dollars on deposit. A HYSA is an ordinary savings account, usually at an online bank, that pays a lot more interest than a typical neighbourhood bank. At a 4.5% APR, $10,000 earns roughly $450 over a year — a touch more once you count monthly compounding (explained in the Compounding note below). This is about as safe as earning yield gets. In the US, money in a bank account is protected by the FDIC — the Federal Deposit Insurance Corporation, a government agency — up to $250,000 per depositor, so even if the bank itself fails you get your dollars back. The simulator treats this strategy as risk-free and doesn't model the rare case of a balance above that insurance limit. Set this to whatever rate your own bank advertises, then watch how the safe savings line stacks up against the riskier strategies on the chart.

Formula: balance next month = balance × (1 + (APR ÷ 12) × (1 − tax rate)) (tax rate is the Global federal-tax assumption)

Compounding: Monthly: APR/12 applied per month boundary.

App default — set by the app's creator, no live data source. Edit if you have a different view.

The last day of the historical window the chop comes from. The most recent N months ending on this date are used (N is the 'Lookback months' below). Pick a window that captures a market regime you want to test against — e.g. late 2022 for crypto-winter chop, late 2024 for the post-election rally. You're not predicting — you're picking a real past period to replay against your scenario.

App default — set by the app's creator, no live data source. Edit if you have a different view.

How many months of historical XRP/USD data to use, ending on the date above. Allowed range 3–60 months. Shorter windows are more recency-biased (less data, more weight on whatever just happened). Longer windows blend more regimes (bull runs, winters, sideways chop) into a single overlay. The default of 36 makes the chop window the same length as a typical simulation horizon.

App default — set by the app's creator, no live data source. Edit if you have a different view.

How strong the chop overlay should be. 0% means no chop (the smooth line shows through unchanged). 10% is subtle texture — the default. 100% replays the historical chop at full amplitude, which makes the chart look noisy and can obscure the scenario shape. Most people find 5–30% reads best.

A 'T-bill' (Treasury bill) is a short-term loan you make to the U.S. government — one of the safest places to put money anywhere, because the government pays it back. A 'tokenized' T-bill is the same thing repackaged as a digital token you can hold in a crypto wallet: a company (the 'wrapper') buys the real T-bills and passes the interest through to you, keeping a small fee. This is the yearly rate (APR = Annual Percentage Rate) you receive after that fee. The rate tracks short-term government interest rates, which is why it lands close to a savings account. The one risk beyond the government itself is the wrapper company — you're trusting it to actually hold the T-bills and stay in business — and that small risk is captured by the LGD knob below.

Formula: balance next month = balance × (1 + (APR ÷ 12) × (1 − tax rate)) (tax rate is the Global federal-tax assumption)

Compounding: Monthly: APR/12 applied per month boundary.

App default — set by the app's creator, no live data source. Edit if you have a different view.

'LGD' stands for Loss-Given-Default — the fraction of your money you'd lose for good if the wrapper company failed, after everything recoverable is collected. It's set LOW here because the thing backing your token is U.S. government debt, which doesn't disappear just because the wrapper company goes bankrupt: in a failure you'd be claiming assets that still exist, much like how brokerage customers are usually made whole when their broker collapses. A 10% LGD means you'd expect to recover about 90 cents on each affected dollar.

Formula: net loss = default magnitude × loss-given-default × current balance (computed per event)

App default — set by the app's creator, no live data source. Edit if you have a different view.

This is the slice of your earnings that goes to U.S. federal income tax, applied as a drag on every strategy that pays yield. 'Marginal rate' means the tax rate on your next dollar of income — for many people that's the 22–24% bracket. The simulator trims each strategy's yield by this percentage, as if you paid the tax each year and reinvested whatever was left. Two things it deliberately does NOT tax. First, simply holding XRP while its price climbs: that's an 'unrealized gain' — a gain on paper only — and isn't taxed until you actually sell, which this simulator doesn't model. Second, state, local, and non-U.S. taxes: not modelled at all. Set it to 0 to see pre-tax numbers, or to your own bracket for a more realistic after-tax picture.

Formula: monthly growth = 1 + (APR ÷ 12) × (1 − tax rate) (applied to the yield, not to principal)

Compounding: The tax rate reduces the yield rate the strategy compounds each month — equivalent to paying tax in the same period the yield arrives and reinvesting the net.

The yearly interest rate (APR = Annual Percentage Rate) you earn by lending out USDC. A few terms first: USDC is a 'stablecoin' — a digital dollar that's meant to always be worth exactly $1, backed by real dollars held in reserve. 'DeFi' (decentralized finance) means lending and borrowing run by open software on a blockchain instead of by a bank. You deposit (the jargon is 'supply') your USDC into a lending app like Aave or Compound, other people borrow it, and you collect interest. It pays more than a bank savings account because it isn't a bank: there's no FDIC insurance, and you're trusting the software (a 'smart contract') not to be hacked and the borrowers' collateral to hold up. In real markets this rate drifts up and down with how much people want to borrow; the simulator holds one steady rate for the whole run so this line stays easy to compare against the others.

Formula: balance next month = balance × (1 + (APR ÷ 12) × (1 − tax rate)) (tax rate is the Global federal-tax assumption)

Compounding: Monthly: APR/12 applied per month boundary.

Live source warming up — range bands appear after the daily refresh has run a few times.

This is the yearly interest rate (APR = Annual Percentage Rate) a lending broker pays you for letting it borrow your XRP. 'XLS-66d' is just the name of the XRP Ledger rulebook these on-chain lending brokers are built on — think of it as the standard that lets a broker take deposits and pay yield. The interest is paid in XRP, so your pile of XRP grows; that's separate from whether XRP's dollar price rises or falls. Different brokers take on different amounts of risk to earn their yield, and that's what this dial represents. As a rough guide: • Conservative brokers pay about 6–9% and lend cautiously. • Moderate brokers pay about 9–12%. • Aggressive brokers pay about 12–20%, but take bigger risks to do it. Higher pay almost always means the broker is reaching for riskier loans — so read this knob together with the First-Loss Buffer and LGD knobs below, which decide how much a borrower failing to repay would actually cost you. Set the APR to match whatever rate a real broker advertises.

Formula: XRP balance next month = XRP balance × (1 + (APR ÷ 12) × (1 − tax rate)) (tax rate is the Global federal-tax assumption)

Compounding: Monthly on the XRP balance — yield accrues in XRP, not USD.

App default — set by the app's creator, no live data source. Edit if you have a different view.

The 'first-loss buffer' is a cushion of the broker's OWN money that gets used up FIRST when borrowers fail to repay — shielding your deposit. It's shown as a fraction of the money you put in: an 8% buffer on a $10,000 deposit means the broker has set aside $800 of its own capital to absorb losses before any loss can reach you. This is the broker's 'skin in the game' — the more of its own money is on the line, the more carefully it tends to lend. Rough guide: cautious brokers run a thick 8–15% buffer; moderate ones 4–8%; aggressive ones a thin 1–4%. A thinner buffer is cheaper for the broker but gets exhausted faster, so a run of bad loans reaches YOUR money sooner. Lower this to model a broker with less of its own skin in the game.

Formula: buffer in USD = first-loss fraction × your deployed capital (fixed at deployment, does not grow)

App default — set by the app's creator, no live data source. Edit if you have a different view.

A 'default' is when a borrower can't pay back a loan. 'LGD' stands for Loss-Given-Default: out of the money tied up in a loan that defaults, the fraction you ultimately lose for good — after everything recoverable has been collected (for instance, by selling off the borrower's 'collateral', the assets they pledged as backing). The rest, (100% − LGD), comes back to you; that returned part is called the 'recovery'. So a 55% LGD means that when a default hits, you eventually get back about 45 cents on each affected dollar and lose the other 55. Rough guide: cautious brokers run 40–60% LGD; moderate 50–70%; aggressive 60–85%. A higher number means weaker collateral and a smaller recovery when things go wrong. Raise it to model a looser, riskier broker.

Formula: net loss = default magnitude × loss-given-default × current balance (computed per event)

App default — set by the app's creator, no live data source. Edit if you have a different view.

'Appreciation' simply means how much the price goes up (or down). This knob is YOUR guess for how much XRP's price will change, in percent, between the day you deploy and the end of the run — and it's the single biggest driver of every strategy that's held in XRP. How to read the number: 0 means flat (no change); 100 means +100% (the price doubles); 1000 means +1000% (the price becomes 11×); −50 means the price is cut in half. Each named scenario comes pre-loaded with a sensible default that fits its story — Slow Bull +100%, Crypto Winter −68%, Holding Pattern 0%, and so on — so picking a scenario fills this in for you. You're then free to override it to ask things like "what would Slow Bull look like if XRP rose 500% instead?" Why it matters so much: for anything held in XRP, your dollar result is simply the amount of XRP you hold times XRP's price. Yield grows the AMOUNT of XRP you own; this knob grows the PRICE of each one — and the two multiply together. That's how an XRP strategy paying 7.5% a year can turn $10,000 into roughly $137,000 if XRP also climbs +1000% over three years. The dollar-based strategies (savings, USDC, T-bills) hold no XRP, so this knob does nothing to them — and watching that contrast on the chart is itself one of the lessons.

Formula: endpoint XRP price = deployment price × (1 + appreciation) · intermediate prices follow the scenario's shape

Compounding: Multiplies through XRP-denominated yield: at any month t, position USD = XRP balance × scenario price at t. Yield grows the XRP balance; this knob grows the price. The two compound in USD.

App default — set by the app's creator, no live data source. Edit if you have a different view.

This only matters when Curve Type is set to 1 (Concentrated Liquidity). It's how tight a price band you pack your money into, measured as a percentage above and below the price on the day you deposit. ±20% means your money is working for prices from 20% below to 20% above your starting price. The trade-off: a tighter band earns dramatically more in fees while the price stays inside it (roughly 5.5× more at ±20%, roughly 10.5× more at ±10%) — but it also magnifies 'impermanent loss' by that same factor, and earns you nothing whenever the price slips outside the band. This is the classic liquidity-provider gamble, made adjustable. The full-range Constant Product curve ignores this knob entirely.

Formula: Inside the band: monthly fees and impermanent loss are both amplified by the same factor. Outside the band: zero fees, and your position holds only the asset that's now out of range.

Compounding: Only consulted when curve type is 1 (ConcentratedLiquidity); ignored otherwise.

App default — set by the app's creator, no live data source. Edit if you have a different view.

This picks HOW the pool spreads your deposited money across possible prices — the difference between earning steady-but-thin fees and concentrated-but-fragile ones. 0 = Constant Product: the standard, simplest kind of pool. Your money is spread thinly across every possible price, from near-zero all the way up. You always earn some fees no matter where the price goes, but the amount is modest. 1 = Concentrated Liquidity: you bunch your money into a narrow price band around today's price (you set how narrow with the next knob). While the price stays inside your band you earn far more in fees; but if the price wanders outside it you earn nothing until it returns, and 'impermanent loss' inside the band is magnified too. It's the same idea as the proposed XRPL 'Swappable Curves' upgrade — see the Glossary for the plain-English version.

Formula: 0 = full-range Constant Product (today's XRPL AMM) · 1 = Concentrated Liquidity (you also pick a price band below)

Compounding: Curve type is fixed for the whole simulation horizon (same as the spec's pool-creation-time immutability).

App default — set by the app's creator, no live data source. Edit if you have a different view.

'Volume' is the total dollar value of swaps flowing through the pool each day. More trading means more fees collected by the pool — and you earn a slice of those fees in proportion to your share of the pool. This is the single biggest lever on how much a liquidity position makes: double the daily volume and you double the fees you earn. When live market data is available this default is refreshed automatically from a public data feed, but you can always type in your own estimate for the pool you're picturing.

Formula: monthly fee revenue (USD) = fee tier × daily volume × your pool share × 30 days

Compounding: Linear in fee revenue; daily figure × 30 = monthly fee throughput for the pool.

App default — set by the app's creator, no live data source. Edit if you have a different view.

First, the setup. An AMM — Automated Market Maker — is software that lets people swap one token for another (here, XRP and RLUSD, a digital dollar that's meant to stay worth $1) out of a shared pot of both tokens called a 'liquidity pool'. If you deposit into that pot you become a 'liquidity provider' and earn a cut of the fees traders pay. The 'fee tier' is the slice the pool skims off every swap. At 0.30%, a trader swapping $1,000 through the pool leaves $3 in fees behind, divided among everyone who supplied the pool. Your personal cut depends on how big your share of the pool is and how much trading flows through it (the next two knobs). Turning this tier up scales everyone's fee earnings straight up.

Formula: monthly fee revenue (USD) = fee tier × daily volume × your pool share × 30 days (added to the pool each month, after tax)

Compounding: Linear in fee revenue; pairs with daily-volume and pool-share knobs.

App default — set by the app's creator, no live data source. Edit if you have a different view.

Your slice of the whole pool. If you supply 0.01% of everything in the pool, you collect 0.01% of the fees it earns. Your share stays fixed for the whole run — the simulator doesn't model you adding more or pulling some out partway through. One subtlety worth knowing: while your SHARE (the percentage) stays put, the dollar VALUE of that share rises and falls as XRP's price moves. Because of the way pools automatically rebalance between the two tokens, a provider can end up with fewer dollars than if they'd simply held the two tokens in their wallet — an effect called 'impermanent loss' (see the Glossary). A bigger share earns more fees but ties up more of your money.

Formula: monthly fee revenue (USD) = fee tier × daily volume × your pool share × 30 days

Compounding: Pool-share stays fixed across the simulation horizon; v1.5 doesn't model adding/withdrawing liquidity mid-run.

App default — set by the app's creator, no live data source. Edit if you have a different view.

Some platforms publish their own headline APR (yearly return) for a pool. This is shown for reference only, so you can compare a platform's advertised number against the return YieldSim actually works out from the fee tier, the trading volume, and your share of the pool. The simulator does NOT feed this number into the chart — your chart line comes from those underlying pieces, not from a platform's marketing figure.

Formula: (observational; from xrpl-utilities.com telemetry payload's amm.top_pairs[XRP/RLUSD].apr)

App default — set by the app's creator, no live data source. Edit if you have a different view.

'TVL' stands for Total Value Locked — the total dollars' worth of tokens currently sitting in the pool. It matters because a bigger pool makes your fixed deposit a SMALLER share of the whole, which earns a smaller slice of the fees. This figure is shown for reference only — the simulator doesn't plug it directly into the math. It's here so you can sanity-check the daily-volume and pool-share numbers against what a real pool actually looks like.

Formula: (observational; from xrpl-utilities.com telemetry payload's amm.top_pairs[XRP/RLUSD].tvl_usd)

App default — set by the app's creator, no live data source. Edit if you have a different view.

The headline APR (yearly return) the marketing splashes across the page — the 2026 launch promo quoted a jaw-dropping 88%. This number is informational ONLY: your chart line is NOT 88%, it's the 'effective' rate (this minus the risk-premium drag below). The whole point of this strategy is to show why a number like 88% almost never survives contact with reality. For context, honest XRP yields run far lower: real liquidity pools make about 5–15%, real institutional XRP lending about 4–8%, and even a generous blend tops out near 12%. An 88% headline gets there by stacking three tricks: (1) Paying you in the protocol's OWN newly-printed token instead of real XRP. That token typically loses 80–95% of its value within a year, so the 'yield' quietly melts away. (2) Cherry-picking a peak — taking a return seen during a brief trading frenzy and advertising it as if it lasted all year. (3) Charging you little during the launch promo, then raising the protocol's cut to 30–40% later (via a rule change the founding team controls) once enough money is locked in.

Formula: (not directly applied — see the Risk-Premium Drag row below for the effective APR)

App default — set by the app's creator, no live data source. Edit if you have a different view.

How much to discount that flashy marketing claim before it touches your chart. Subtracting this 'drag' from the claimed APR gives the EFFECTIVE (realistic) rate that actually compounds. It bundles together eight separate ways an auto-routing yield product can quietly cost you: 1. Smart-contract risk — a bug or hack in the router software itself. 2. Impermanent loss — when XRP's price moves, the automated pools hand back less XRP than you put in (see the Glossary). 3. Borrower default — even 'vetted' big borrowers go bust (the hedge fund 3AC was considered rock-solid right up until it collapsed in 2022). 4. Knock-on failures — the router stacks many pools on top of one another, so a problem in any single one can cascade through into your balance. 5. Token-collapse — most of the advertised yield is paid in the protocol's own token; if that token drops 90% after launch, the 'yield' was never really there. 6. Worst-pool selection — auto-routers tend to dump deposits into whichever pool has the most room, which is often the least healthy one. 7. Lockups — a 30–90 day withdrawal queue means you can't get out fast when the headline falls apart. 8. Fee hikes — the protocol's cut can be raised later by a vote the founding team controls. The default 78% drag against an 88% claim leaves 10% effective — right in the realistic yield band, comparable to a moderate XLS-66d broker. Dial it DOWN (say 0.04) to see what the marketing number alone would produce; dial it UP for a more skeptical view. (It can't go above the claimed rate — the math won't let drag alone create a loss.)

Formula: effective APR = claimed APR − risk-premium drag · XRP balance next month = XRP balance × (1 + (effective APR ÷ 12) × (1 − tax rate))

Compounding: Subtracted from claimed APR; never exceeds claimed (strict invariant — engine throws).