diff --git a/packages/ag-trade/src/auction-bid.js b/packages/ag-trade/src/auction-bid.js
new file mode 100644
index 0000000..665a037
--- /dev/null
+++ b/packages/ag-trade/src/auction-bid.js
@@ -0,0 +1,181 @@
+// @ts-check
+import { E } from '@endo/far';
+import { M, mustMatch, matches } from '@endo/patterns';
+
+import { AmountShape } from './typeGuards.js';
+import { parseRatio } from './parseRatio.js';
+
+/** @template T @typedef {import('@endo/eventual-send').ERef<T>} ERef */
+
+const { Fail } = assert;
+const UNIT6 = 1_000_000n;
+
+/**
+ * @template T
+ * @param {T | null | undefined } x
+ * @returns {T}
+ */
+const NonNullish = x => {
+  if (x === undefined || x === null) throw assert.error('NonNullish');
+  return x;
+};
+
+/**
+ * @param {{
+ *   offerId: string;
+ *   give: import('./types.js').Amount<'nat'>;
+ *   maxBuy: import('./types.js').Amount<'nat'>;
+ *   wantMinimum?: import('./types.js').Amount<'nat'>;
+ * } & (
+ *   | {
+ *       price: number;
+ *     }
+ *   | {
+ *       discount: number; // -1 to 1. e.g. 0.10 for 10% discount, -0.05 for 5% markup
+ *     }
+ * )} opts
+ * @returns {import('./types.js').OfferSpec}
+ */
+const makeBidOffer = opts => {
+  mustMatch(
+    harden({
+      offerId: opts.offerId,
+      give: opts.give,
+      maxBuy: opts.maxBuy,
+    }),
+    harden({
+      offerId: M.or(M.string(), M.number()),
+      give: AmountShape,
+      maxBuy: AmountShape,
+    }),
+  );
+  const proposal = {
+    give: { Bid: opts.give },
+    ...(opts.wantMinimum ? { want: { Collateral: opts.wantMinimum } } : {}),
+  };
+  const istBrand = proposal.give.Bid.brand;
+  const maxBuy = opts.maxBuy;
+
+  const bounds = (x, lo, hi) => {
+    assert(x >= lo && x <= hi);
+    return x;
+  };
+
+  assert(
+    'price' in opts || 'discount' in opts,
+    'must specify price or discount',
+  );
+  const offerArgs =
+    'price' in opts
+      ? {
+          maxBuy: opts.maxBuy,
+          offerPrice: parseRatio(opts.price, istBrand, maxBuy.brand),
+        }
+      : {
+          maxBuy,
+          offerBidScaling: parseRatio(
+            (1 - bounds(opts.discount, -1, 1)).toFixed(2),
+            istBrand,
+            istBrand,
+          ),
+        };
+
+  /** @type {import('./types.js').OfferSpec} */
+  const offerSpec = {
+    id: opts.offerId,
+    invitationSpec: {
+      source: 'agoricContract',
+      instancePath: ['auctioneer'],
+      callPipe: [['makeBidInvitation', [maxBuy.brand]]],
+    },
+    proposal,
+    offerArgs,
+  };
+  return offerSpec;
+};
+
+/**
+ * @param {string[]} args
+ * @param {{ [k: string]: boolean | undefined }} [style]
+ */
+const getopts = (args, style = {}) => {
+  /** @type {{ [k: string]: string}} */
+  const flags = {};
+  while (args.length > 0) {
+    const arg = NonNullish(args.shift());
+    if (arg.startsWith('--')) {
+      const name = arg.slice('--'.length);
+      if (style[name] === true) {
+        flags[name] = '';
+        continue;
+      }
+      if (args.length <= 0) throw RangeError(`no value for ${arg}`);
+      flags[name] = NonNullish(args.shift());
+    }
+  }
+  return harden(flags);
+};
+
+/**
+ * @param {*} self
+ * @param {string[]} args
+ */
+export const main = async (self, ...args) => {
+  const flags = getopts(args, { list: true });
+  /** @type {import("./smartWallet.js").WalletKit} */
+  const { query: vstorage, smartWallet } = await E(self).lookup('wallet');
+
+  if ('list' in flags) {
+    const info = await E(E(smartWallet).readOnly()).current();
+    console.log('live offers', info.liveOffers);
+    console.log('purse balances', info.purses);
+    return;
+  } else {
+    mustMatch(
+      flags,
+      M.splitRecord(
+        { give: M.string(), discount: M.string(), maxBuy: M.string() },
+        { wantMinimum: M.string() },
+      ),
+    );
+  }
+
+  const vse = await E(
+    E(vstorage).lookup('agoricNames', 'vbankAsset'),
+  ).entries();
+  const byName = Object.fromEntries(
+    vse.map(([_denom, info]) => [info.issuerName, info]),
+  );
+  console.log('vbankAssets', Object.keys(byName));
+
+  /** @param {string} flag */
+  const parseAmount = flag => {
+    if (!(flag in flags)) throw Error(`missing ${flag}`);
+    const arg = flags[flag];
+    const [numeral, brandName] = arg.split(' ');
+    brandName in byName || Fail`unknown brand: ${brandName}`;
+    const { brand, displayInfo } = byName[brandName];
+    const { decimalPlaces } = displayInfo;
+    const value = BigInt(Number(numeral) * 10 ** decimalPlaces);
+    /** @type {import('./types').Amount<'nat'>} */
+    const amt = { brand, value };
+    return amt;
+  };
+
+  /** @type {ERef<import('./fresh-id').Fresh>} */
+  const fresh = E(self).lookup('fresh');
+  const id = await E(fresh).next();
+
+  const offerSpec = makeBidOffer({
+    offerId: id,
+    give: parseAmount('give'),
+    maxBuy: parseAmount('maxBuy'),
+    ...('wantMinimum' in flags && {
+      wantMinimum: parseAmount('wantMinimum'),
+    }),
+    discount: Number(flags['discount']),
+  });
+
+  const info = await E(smartWallet).executeOffer(offerSpec);
+  return info;
+};