Bond yield to maturity

Solve a bond's yield to maturity from its market price — the annual rate that present-values the coupons plus face to that price. Bracketed bisection root-find.

Input

Field	Type	Description
price *	number	Current market (clean) price
faceValue *	number	Par/face value
couponRate *	number	Annual coupon rate as decimal
years *	number	Years to maturity
periodsPerYear	number	Coupon periods per year. Default 2.

Example output

{
  "yieldToMaturity": 0.06,
  "periods": 20,
  "converged": true
}

Try it — see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/bond-ytm \
  -H "Content-Type: application/json" \
  -d '{"price":925.61,"faceValue":1000,"couponRate":0.05,"years":10,"periodsPerYear":2}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/bond-ytm", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "price": 925.61,
    "faceValue": 1000,
    "couponRate": 0.05,
    "years": 10,
    "periodsPerYear": 2
  }),
});

No wallet? Pay with compute

This is a pure-CPU tool, so an agent without a wallet can pay with proof-of-work instead of USDC: fetch a challenge, solve the sha256 puzzle (16 leading zero bits — a fraction of a second of CPU, no money, no AI tokens), and resend with the X-Pow-Solution header.

import { createHash } from "node:crypto";
const lz = (b) => { let t = 0; for (const x of b) { if (!x) { t += 8; continue; } t += Math.clz32(x) - 24; break; } return t; };
const c = await (await fetch("https://agent402.tools/api/pow/challenge?slug=bond-ytm")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/bond-ytm", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"price":925.61,"faceValue":1000,"couponRate":0.05,"years":10,"periodsPerYear":2}) });

Part of these workflows

This tool is one step in a curated multi-tool workflow — agents can fetch the whole sequence as an MCP prompt or call https://agent402.tools/api/skill-packs/{slug}/prompt.

• Fixed-income desk — Read the rate environment and price a bond in one workflow: the live Treasury curve, the recession-signal spread, inflation context, then price and yield a specific coupon bond at current rates.

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