Lending

Earn yield by filling borrowers' limit orders with USDC. You provide USDC now and receive the borrower's collateral (WETH or cbBTC) at expiry if the option is exercised.

How Lending Works

Note (v0.2.1 / Base_r12): the contract no longer supports converting an unfilled RFQ into a limit order. The keepOrderOpen flag on LoanRequest is now a no-op deprecation. The lending workflow described below remains applicable only to historical loans tracked by the indexer that already carry that flag; new r12 loans will not surface here.

When a borrower enabled keepOrderOpen: true (pre-r12) and no market maker filled during the initial auction, the request became a limit order. Any user could fill it by providing the requested USDC amount.

At expiry, if the borrower exercises (repays), you receive your USDC back plus the spread. If the borrower walks away, you receive the collateral instead.

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Browse Lending Opportunities

import { ethers } from 'ethers';
import { ThetanutsClient } from '@thetanuts-finance/thetanuts-client';

const provider = new ethers.JsonRpcProvider('https://mainnet.base.org');
const signer = new ethers.Wallet(process.env.PRIVATE_KEY!, provider);
const client = new ThetanutsClient({ chainId: 8453, provider, signer });

// Fetch all available limit orders
const opps = await client.loan.getLendingOpportunities();

for (const o of opps) {
  console.log(`#${o.quotationId} | ${o.underlying}`);
  console.log(`  Collateral: ${o.collateralFormatted} ${o.underlying}`);
  console.log(`  Provide:    ${o.lendAmountFormatted} USDC`);
  console.log(`  Strike:     $${o.strike}`);
  console.log(`  Expiry:     ${o.expiryFormatted}`);
  console.log(`  APR:        ${o.aprFormatted}%`);
}

Filter by Underlying

// Only ETH-collateralized loans
const ethOpps = await client.loan.getLendingOpportunities({
  underlying: 'ETH',
});

// Only BTC-collateralized loans
const btcOpps = await client.loan.getLendingOpportunities({
  underlying: 'BTC',
});

Exclude Your Own Loans

const userAddress = await signer.getAddress();
const opps = await client.loan.getLendingOpportunities({
  excludeAddress: userAddress,
});

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Fill a Limit Order

Filling a limit order calls OptionFactory.settleQuotation() under the hood. You must approve USDC to the OptionFactory contract first.

const opp = opps[0]; // Pick an opportunity

// Approve USDC to OptionFactory
const factoryAddress = client.chainConfig.contracts.optionFactory;
await client.erc20.ensureAllowance(
  '0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913', // USDC
  factoryAddress,
  opp.lendAmount
);

// Fill the loan
const receipt = await client.loan.lend(BigInt(opp.quotationId));
console.log(`Filled loan #${opp.quotationId}: ${receipt.hash}`);

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Lending Opportunity Fields

Field	Type	Description
quotationId	string	Quotation ID to pass to lend()
requester	string	Borrower's address
underlying	string	'ETH' or 'BTC'
collateralFormatted	string	Collateral amount (e.g. "1.5")
lendAmountFormatted	string	USDC to provide (e.g. "1422.41")
lendAmount	bigint	Raw USDC amount (6 decimals)
strike	number	Strike price in USD
expiryTimestamp	number	Expiry Unix timestamp
expiryFormatted	string	Human-readable expiry date
apr	number	Estimated lender APR
aprFormatted	string	APR as string (e.g. "12.50")
raw	LoanIndexerLoan	Full indexer response

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See Also

• Overview — Module overview and cost formula

• Borrowing — Request loans as a borrower