Latest backtest update (2026-04): Based on FuNi’s historical rate database (data range 2019-04 to 2026-03, USD pool samples, year-by-year walk-forward windows (2020 to 2026)), our latest backtest shows that the APEX III strategy produced a pre-fee annualized return of roughly 8%–16% over about 180–365 days across the USD and USDT lending markets, and a USD pool average of about 11% after the 15% platform fee, with peaks around 80% (extreme outliers tied to systemic events like LUNA or FTX, not the norm); the baseline ran around 6%–7% long-term. Across the multi-year time windows (2019–2026, seven yearly windows per currency), the APEX III backtest return was higher than the baseline in all seven yearly windows for the USD pool, and in six of seven for USDT.

Risk note: The above reflects a historical backtest period, simulated by running the APEX III strategy on Bitfinex’s public lending-rate data, and does not represent future results. Crypto lending rates are affected by market liquidity, BTC/USDT volatility, platform funding demand, and many other factors; actual returns may be higher or lower than this range. FuNi Bot provides strategy tools and does not promise any return—users must assess their own risk.

When you lend on Bitfinex, you immediately face a choice: should you lend US dollars (USD), or USDT? Both are pegged 1:1 to the US dollar, and their rates look about the same. But the moment you actually dive in, you’ll find that the two differ noticeably in deposit path, funding book depth, historical annualized rates, and even risk structure.

This article lays out the real, multi-year rate data we’ve accumulated in our historical rate database (2019-04 to 2026-03), cross-references it with the Q1 2026 Tether transparency report and the actual deposit experience of Taiwanese users, and answers one core question for you: on Bitfinex, how should you choose between USD and USDT lending?


1. The Basic Difference Between USD and USDT

Let’s clear up the most easily confused point first: USD is fiat US dollars, while USDT is the dollar-pegged stablecoin issued by Tether. On the Bitfinex lending market they exist as two separate funding books—USD and USDT—with rates matched independently and no shared funding pool.

Comparison itemUSD (US dollars)USDT (Tether)
Asset natureFiat (real US dollars)Stablecoin (pegged to USD)
Bitfinex lending codeUSDUSDT
Deposit methodBank wire (SWIFT), minimum $10,000On-chain transfer (TRC-20, ERC-20, SOL, etc.)
Deposit arrival time2–5 business daysDepends on the sending exchange’s processing and network congestion; Bitfinex’s public pages do not list arrival times per network
Deposit fee0.1% (minimum $60)Depends on the exchange; go by its withdrawal page
Verification levelFull for a USD wire (Intermediate to lend)Basic Plus to deposit (Intermediate to lend)
Funding book depthLarge but more concentratedSlightly larger, more orders, smaller average size
180–365 day APEX III pre-fee rangeAbout 8%–16%About 8%–16%
Combined the USD pool average after 15% platform feeAbout 11%About 11%
Rare peak (short-term)About 80% (extreme outlier tied to systemic events like LUNA or FTX, not the norm)About 80% (extreme outlier tied to systemic events like LUNA or FTX, not the norm)
Main riskBitfinex custody riskBitfinex custody + Tether reserve risk
Difficulty for Taiwanese usersVery high (Taiwan bank wires reported unavailable; needs a non-Taiwan bank)Low (buy on MAX or BitoPro, then transfer on-chain)

This table is the map for everything that follows. Don’t worry if it doesn’t all make sense yet—each section below breaks it down.


2. Funding Book Liquidity: USDT Has More Orders, USD Has Larger Single Orders

Bitfinex’s funding book is the matching core for both USD and USDT lending, but the participant structures on each side are actually different.

  • USD market: common users are institutions and seasoned players who have already passed Intermediate KYC and hold overseas bank accounts. The funding book is characterized by “fewer orders, larger sizes”—offers commonly start at $10,000 and can even reach single lending offers in the $500,000 to $1,000,000 range.
  • USDT market: common users are everyday crypto users and Asian retail participants. The funding book is characterized by “more orders, smaller sizes”—offers from 150 USDT (Bitfinex’s minimum) up to a few thousand USDT are very dense.

Based on the long-term data we track in our historical rate database, the total depth of the USDT funding book is normally slightly larger than USD’s. But institutional capital in the USD market can more easily stack a “wall” at the same price level, so rates actually swing more sharply—one of the key reasons USD’s market-timing returns beat USDT’s in historical backtests.

Tether Treasury transferred hundreds of millions of USDT into Bitfinex several times in Q1 2026 to replenish liquidity, signaling that the exchange’s leveraged-borrowing side still has strong demand for USDT. That “borrowing demand” is the fundamental source of lending rates.


3. Historical Rate Difference: USD Averages 2–3 Percentage Points Higher Than USDT

Many articles claim “USD and USDT rates are about the same.” That’s true on short timescales (a few days to a week), but stretch the horizon to a quarter, half a year, or a full year and the gap becomes clear.

We ran an APEX III strategy backtest using our historical rate database (2019-04 to 2026-03, multi-year USD + USDT samples), with the results below:

The backtest shows that USD and USDT trade relative leadership across different time windows—broadly, USD edged ahead in some high-volatility years, while USDT won out in years of strong on-chain capital inflow. The 180–365 day APEX III pre-fee range is about 8%–16%, with a USD pool average of about 11% after the 15% platform fee, and you can observe extreme peaks around 80% (short-term, not the norm). USD led USDT by about 2–3 percentage points in some years, for three reasons:

  1. USD rates are more volatile, so APEX III’s dynamic-duration strategy gets more chances to “lock in long-term orders when rates spike.”
  2. USDT supply grows faster (easy on-chain deposits keep new capital pouring in), pushing the long-term average rate down.
  3. The USD borrowing side often involves institutional leverage, so short-term rates get pushed up quickly when markets move—forming the strategy’s main source of excess return.

But this does not mean “lending USD always wins.” Across the multi-year, multi-asset time windows, USDT actually won in some windows (usually late in a bull market, when on-chain USDT demand surges). The APEX III backtest return being higher than the baseline in all seven yearly windows for the USD pool, and in six of seven for USDT, is an overall statistical result, not a guarantee for any single time window.

Risk note: The 8%–16% above is a historical backtest range, simulated by running the APEX III strategy on Bitfinex’s public lending-rate data. Past performance does not represent future results; crypto lending rates are affected by market liquidity, BTC/USDT volatility, Bitfinex platform funding demand, and many other factors, so actual results may be higher or lower than this range.


4. USDT’s Unique Risk: Tether Reserves and Regulation

The risk of USD lending is basically just Bitfinex’s exchange custody risk. USDT adds one more layer: the credit and reserves of Tether the company itself. A few facts laid out in Q1 2026 are worth lenders looking at together:

  • Issuance: USDT’s circulating supply was about $183 billion at the end of Q1 2026 (per official attestation), making it the world’s largest dollar stablecoin.
  • Reserve composition: per Tether’s published attestation reports, reserves consist mainly of US Treasury bills, money market funds, cash and equivalents, plus small amounts of gold, Bitcoin, and secured loans; for the exact proportions, refer to Tether’s latest official disclosures.
  • Audit progress: Tether has publicly stated it will engage an accounting firm to conduct a more complete audit of its reserves; details are subject to official announcements.
  • Regulatory pressure: some rating agencies remain cautious about the share of volatile assets in USDT’s reserves, and the reserves’ resilience under market stress scenarios is still a point of attention.

What this means in practice for lenders:

  • Short-term lending (2–30 days): the annualized impact of Tether credit risk is extremely low, but during black-swan events (such as the 2022 UST depeg chain reaction) USDT briefly dropped to $0.95, and you can’t immediately cancel and exit a long-duration order at the moment of a depeg.
  • Long-term lending (over 30 days): treat USDT as an asset that carries “one extra layer of issuer credit beyond cash,” and set aside some USD or spot hedging positions to avoid single structural risk.
  • General users: keeping mostly short locks and making good use of auto-cancel and asset-swap features keeps the risk manageable.

5. The Real Choice for Taiwanese Users: USDT Is the More Practical Entry Point

If you’re in Taiwan, this section matters more than the rates. Look at reality first:

  • Bitfinex fiat wire deposits go through SWIFT, with a $10,000 minimum and a 0.1% fee (minimum $60); add intermediary bank charges and the actual amount received often gets shaved by another $30–50.
  • Wires from Taiwan banks are reported to be no longer accepted. According to user reports and Taiwanese media (we found no separate public announcement from Bitfinex), a notice in the Bitfinex app says that, under Taiwanese regulations, Bitfinex no longer handles fiat wires through banks in Taiwan, including the Taiwan branches of foreign banks, for individuals or companies. Some Taiwan banks had already refused Bitfinex wires on their own (reported in 2022 and 2024). The start date is unconfirmed: forum posts from April 2026 mention a cut-off around 29 April, which we could not verify. Compiled by this site in October 2026; check your own Bitfinex account for the current status.
  • Withdrawals are just as troublesome: wiring dollars out requires Full verification and a 10,000 USD minimum (fees from 100 USD, normally 5–10 business days), and per the reports above a Taiwan bank is no longer a usable destination.

By contrast, the USDT path is:

  1. Buy USDT with New Taiwan dollars on local compliant exchanges such as MAX or BitoPro.
  2. Choose a network that both Bitfinex and your sending exchange support, such as TRC-20 or ERC-20. The withdrawal fee depends on the network and the exchange and changes with network conditions, so go by the amount shown on the sending exchange’s withdrawal page. As checked in October 2026, neither MAX nor BitoPro supports USDT on Solana, so Solana is not an option from these two.
  3. Withdraw to your Bitfinex USDT deposit address; the arrival time depends on the sending exchange’s processing and network congestion, and Bitfinex’s public pages do not list arrival times per network.
  4. Move it into your Funding (lending) wallet and start placing offers.

That’s also why many Taiwanese users lean toward USDT with USD as a supplement—not because people don’t want to earn the extra 2–3 percentage points from USD, but because USD’s deposit friction is too high to make sense for small and mid-sized capital.

Note (as checked in October 2026): TRC-20 withdrawals cost more than ERC-20, Polygon and BEP20 withdrawals at both exchanges, but exchanges can change this at any time, so go by the withdrawal page. The on-chain cost on TRON is also higher than on Polygon or BEP20. The reason is the mechanism: moving USDT on TRON consumes energy, and the USDT contract is marked up by TRON’s dynamic energy model, which is where most of the cost comes from. The cost is priced in TRX, so its dollar value moves with the TRX price. TRON cut its energy price in late August 2025, and that price can change again. This on-chain cost only comes up if you send from your own wallet; when you withdraw from an exchange, you only pay the withdrawal fee shown on its withdrawal page and do not need to burn any TRX yourself. Also, Bitfinex’s published list of USDt networks does not include BNB Smart Chain (BEP20), so do not deposit over BEP20; Bitfinex accepts USDT sent over Polygon but credits it as USDT0, which you must first convert into USDt on the wallet page before lending (USDT0 cannot be traded directly; Bitfinex’s March 2025 announcement says 1-to-1, and whether the conversion has a fee should be checked on the wallet page).

Suggested paths:

  • Under $20,000: just use USDT—don’t wire money over for an extra 2 percentage points of annualized yield.
  • $20,000–$100,000 with an overseas bank account outside Taiwan: consider routing part of your capital via USD wire to diversify single-stablecoin-issuer risk.
  • Over $100,000: a dual USD + USDT allocation is standard—let the bot automatically park your money on whichever side has the higher rate.

6. How Does FuNi Handle USD and USDT at the Same Time?

FuNi Bot was designed from the start to lend in both assets (USD + USDT) simultaneously. It’s not “two bots” but one APEX III strategy placing orders on both the USD and USDT funding books at once:

  • Independent forecasts for each: APEX III (our strategy engine) maintains separate forecast models for USD and USDT, with no cross-contamination.
  • Automatic duration selection: APEX III dynamically adjusts lock durations based on the rate level—locking longer durations when rates are high, using medium durations when moderate, and keeping short locks for flexibility when rates are low—with USD and USDT each run separately.
  • Automatic order splitting: it automatically splits based on the offer amount and Bitfinex’s 150 USD/USDT minimum, so no single order gets stuck.
  • Scan interval: 60 minutes on Free, 15 on Entry, 5 on PRO, 2 on VIP (VIP accelerates to 30 seconds on abnormal rate spikes).
  • Daily Telegram earnings report: available on every plan once Telegram is connected. Checks start at 09:30 Taiwan time and the report goes out as soon as the day’s interest has been credited, one message per currency (USD and USDT) with the day’s earnings, month-to-date earnings, amount lent out and average annualized rate.

For you, all you have to do is move both assets into your Bitfinex Funding wallet, and the bot handles the rest—timing, lock durations, and cancellations—so you never have to switch between the two markets manually.


7. FAQ: Common Questions About USD vs USDT Lending

Q1. If USD wins on average in some years, why not just lend everything in USD?

Because for the typical Taiwanese user, USD’s deposit friction (the $10,000 wire threshold, fees, KYC) often eats up that few-percentage-point lead; and once capital is in USD it’s hard to pull back quickly, far less flexible than USDT. In the multi-year tests, USDT also won in plenty of time windows, so going all-in on USD is not necessarily the better choice.

Q2. What happens to my lending order if USDT depegs?

A lending order itself is “lend out USDT, get back USDT + interest,” so during a depeg the balance is still denominated in USDT and does not automatically convert into dollars. At the moment of a depeg, a long-duration order can’t be unlocked early. Practical advice: keep mostly short durations day-to-day, and only lock long durations when rates are high; and don’t put all your assets in a single stablecoin.

Q3. Is the interest earned from USD lending paid in dollars? Can I withdraw it directly to a Taiwanese bank?

Yes, it’s in dollars, but withdrawing it as fiat requires Bitfinex Full verification and a bank wire (minimum 10,000 USD, fees from 100 USD plus intermediary bank charges), and per user reports Bitfinex no longer handles fiat wires through Taiwan banks (see section 5; compiled by this site in October 2026). A common approach is to convert USD into USDT first, then withdraw on-chain to a local exchange and convert back into New Taiwan dollars.

Q4. If I lend in both assets, does diversification actually make things worse?

No. Because the two funding books are matched independently, the USD and USDT rate peaks are not fully synchronized (sometimes USD spikes first, sometimes USDT does). A dual-asset allocation actually reduces idle gaps in a single market and balances capital utilization more evenly. FuNi’s strategy engine is precisely using this lack of synchronization to time both at once.

Q5. I only have 1,000 USDT—is it worth starting to lend?

It’s worth trying, but don’t expect quick riches. At an after-fee average of about 11% annualized, 1,000 USDT earns roughly 9 USDT of interest in a month. The point at this stage is to get familiar with Bitfinex, understand funding book volatility, and build a long-term interest re-lending habit—the value of strategy differences only shows once your capital grows.


8. Conclusion: Pick the Right Entry First, Then Optimize Strategy

Breaking USD and USDT lending down to the core:

  • USD has a slightly higher long-term annualized yield, but a high deposit threshold and low flexibility—best for users with large capital who already hold overseas bank accounts.
  • USDT moves freely on-chain and has good funding book depth; it’s the more practical entry point for Taiwanese users, and it’s the natural lending target for crypto assets.
  • Dual-asset is the most hassle-free allocation, letting the bot automatically time the two markets for you—giving up a few extreme outliers in exchange for greater overall stability.

What matters isn’t rigidly sticking to one asset, but keeping your capital from sitting idle. As long as an offer is placed, it earns interest, and as long as the interest keeps being re-lent, the few percentage points between USD and USDT will matter far less over the long run than you’d think.

If you don’t yet have an automation tool, click the button below to try FuNi free for up to 21 days and experience the APEX III lending engine placing USD and USDT offers at the same time.


Further Reading


Disclaimer

This content is for general informational reference only and does not constitute investment advice. Crypto lending involves market risk, and past performance does not represent future results. APEX III is FuNi’s internal strategy name, not a financial product. Bitfinex is an independent third-party platform, and FuNi is not an official Bitfinex partner. Please assess your own risk before investing, and consult a professional financial advisor if needed.