diff --git a/src/builders.rs b/src/builders.rs
index 5acd598..ded7762 100644
--- a/src/builders.rs
+++ b/src/builders.rs
@@ -150,7 +150,7 @@ impl MsgCreateTaskBuilder {
 #[derive(Builder)]
 pub struct MsgCreatePin {
     pub creator: String,
-    pub cid: String,
+    pub cid: Option<String>,
     pub bytes: ByteSize,
     pub name: String,
     pub redundancy: u64,
@@ -168,7 +168,7 @@ impl MsgCreatePinBuilder {
             .map_err(|e| Error::EncodeError(e.to_string()))?;
         Ok(gevulot::MsgCreatePin {
             creator: msg.creator,
-            cid: msg.cid,
+            cid: msg.cid.unwrap_or_default(),
             bytes: msg.bytes.to_bytes(),
             name: msg.name,
             redundancy: msg.redundancy,
diff --git a/src/lib.rs b/src/lib.rs
index e0dca59..b364941 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -146,7 +146,7 @@ mod tests {
         // Create a pin
         let pin_msg = builders::MsgCreatePinBuilder::default()
             .creator(address.clone())
-            .cid("QmSWeBJYvDqKUFG3om4gsrKGf379zk8Jq5tYXpDp7Xo".to_string())
+            .cid(Some("QmSWeBJYvDqKUFG3om4gsrKGf379zk8Jq5tYXpDp7Xo".to_string()))
             .bytes((32, Byte).into())
             .time(3600)
             .redundancy(1)