diff --git a/CHANGELOG.md b/CHANGELOG.md
index 875719fe..0536d683 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,8 @@ and this project adheres to
 
 - @cosmjs/cosmwasm-stargate: Use `CosmWasmFeeTable` instead of `CosmosFeeTable`
   in `SigningCosmWasmClientOptions`; export type `CosmWasmFeeTable`.
+- @cosmjs/amino, @cosmjs/cli, @cosmjs/ledger-amino, @cosmjs/proto-signing: Fix
+  runtime error caused by passing explicitly undefined options.
 
 ## [0.25.0] - 2021-05-05
 
diff --git a/packages/amino/src/secp256k1hdwallet.spec.ts b/packages/amino/src/secp256k1hdwallet.spec.ts
index 92aa78a9..c55085d1 100644
--- a/packages/amino/src/secp256k1hdwallet.spec.ts
+++ b/packages/amino/src/secp256k1hdwallet.spec.ts
@@ -33,6 +33,18 @@ describe("Secp256k1HdWallet", () => {
       expect(account.pubkey).not.toEqual(defaultPubkey);
       expect(account.address.slice(0, 4)).toEqual("yolo");
     });
+
+    it("works with explicitly undefined options", async () => {
+      const wallet = await Secp256k1HdWallet.fromMnemonic(defaultMnemonic, {
+        bip39Password: undefined,
+        hdPaths: undefined,
+        prefix: undefined,
+      });
+      expect(wallet.mnemonic).toEqual(defaultMnemonic);
+      const [account] = await wallet.getAccounts();
+      expect(account.pubkey).toEqual(defaultPubkey);
+      expect(account.address).toEqual(defaultAddress);
+    });
   });
 
   describe("generate", () => {
diff --git a/packages/amino/src/secp256k1hdwallet.ts b/packages/amino/src/secp256k1hdwallet.ts
index 56a65f23..2c224e31 100644
--- a/packages/amino/src/secp256k1hdwallet.ts
+++ b/packages/amino/src/secp256k1hdwallet.ts
@@ -246,12 +246,13 @@ export class Secp256k1HdWallet implements OfflineAminoSigner {
   private readonly accounts: readonly DerivationInfo[];
 
   protected constructor(mnemonic: EnglishMnemonic, options: Secp256k1HdWalletConstructorOptions) {
-    const { seed, hdPaths, prefix } = { ...defaultOptions, ...options };
+    const hdPaths = options.hdPaths ?? defaultOptions.hdPaths;
+    const prefix = options.prefix ?? defaultOptions.prefix;
     this.secret = mnemonic;
-    this.seed = seed;
+    this.seed = options.seed;
     this.accounts = hdPaths.map((hdPath) => ({
       hdPath: hdPath,
-      prefix: prefix,
+      prefix,
     }));
   }
 
diff --git a/packages/cli/examples/helpers.ts b/packages/cli/examples/helpers.ts
index 8b229e7f..29652aad 100644
--- a/packages/cli/examples/helpers.ts
+++ b/packages/cli/examples/helpers.ts
@@ -30,7 +30,13 @@ const connect = async (
   client: SigningCosmWasmClient;
   address: string;
 }> => {
-  const options: Options = { ...defaultOptions, ...opts };
+  const options: Options = {
+    bech32prefix: opts.bech32prefix ?? defaultOptions.bech32prefix,
+    feeToken: opts.feeToken ?? defaultOptions.feeToken,
+    gasPrice: opts.gasPrice ?? defaultOptions.gasPrice,
+    httpUrl: opts.httpUrl ?? defaultOptions.httpUrl,
+    networkId: opts.networkId ?? defaultOptions.networkId,
+  };
   const gasPrice = GasPrice.fromString(`${options.gasPrice}${options.feeToken}`);
   const wallet = await Secp256k1HdWallet.fromMnemonic(mnemonic);
   const [{ address }] = await wallet.getAccounts();
diff --git a/packages/ledger-amino/src/launchpadledger.ts b/packages/ledger-amino/src/launchpadledger.ts
index 01eb512a..0e58bd40 100644
--- a/packages/ledger-amino/src/launchpadledger.ts
+++ b/packages/ledger-amino/src/launchpadledger.ts
@@ -44,13 +44,10 @@ export class LaunchpadLedger {
       prefix: cosmosBech32Prefix,
       testModeAllowed: false,
     };
-    const { hdPaths, prefix, testModeAllowed } = {
-      ...defaultOptions,
-      ...options,
-    };
-    this.testModeAllowed = testModeAllowed;
-    this.hdPaths = hdPaths;
-    this.prefix = prefix;
+
+    this.testModeAllowed = options.testModeAllowed ?? defaultOptions.testModeAllowed;
+    this.hdPaths = options.hdPaths ?? defaultOptions.hdPaths;
+    this.prefix = options.prefix ?? defaultOptions.prefix;
     this.app = new CosmosApp(transport);
   }
 
diff --git a/packages/proto-signing/src/directsecp256k1hdwallet.spec.ts b/packages/proto-signing/src/directsecp256k1hdwallet.spec.ts
index fe580c00..537b9bc9 100644
--- a/packages/proto-signing/src/directsecp256k1hdwallet.spec.ts
+++ b/packages/proto-signing/src/directsecp256k1hdwallet.spec.ts
@@ -31,6 +31,18 @@ describe("DirectSecp256k1HdWallet", () => {
       expect(pubkey).not.toEqual(defaultPubkey);
       expect(address.slice(0, 4)).toEqual("yolo");
     });
+
+    it("works with explicitly undefined options", async () => {
+      const wallet = await DirectSecp256k1HdWallet.fromMnemonic(defaultMnemonic, {
+        bip39Password: undefined,
+        hdPaths: undefined,
+        prefix: undefined,
+      });
+      expect(wallet.mnemonic).toEqual(defaultMnemonic);
+      const [{ pubkey, address }] = await wallet.getAccounts();
+      expect(pubkey).toEqual(defaultPubkey);
+      expect(address).toEqual(defaultAddress);
+    });
   });
 
   describe("generate", () => {
diff --git a/packages/proto-signing/src/directsecp256k1hdwallet.ts b/packages/proto-signing/src/directsecp256k1hdwallet.ts
index e6c993ab..b1e23a82 100644
--- a/packages/proto-signing/src/directsecp256k1hdwallet.ts
+++ b/packages/proto-signing/src/directsecp256k1hdwallet.ts
@@ -91,9 +91,10 @@ export class DirectSecp256k1HdWallet implements OfflineDirectSigner {
   private readonly accounts: readonly Secp256k1Derivation[];
 
   protected constructor(mnemonic: EnglishMnemonic, options: DirectSecp256k1HdWalletConstructorOptions) {
-    const { seed, hdPaths, prefix } = { ...defaultOptions, ...options };
+    const prefix = options.prefix ?? defaultOptions.prefix;
+    const hdPaths = options.hdPaths ?? defaultOptions.hdPaths;
     this.secret = mnemonic;
-    this.seed = seed;
+    this.seed = options.seed;
     this.accounts = hdPaths.map((hdPath) => ({
       hdPath: hdPath,
       prefix: prefix,