diff --git a/oid4vc-core/src/subject_syntax_type.rs b/oid4vc-core/src/subject_syntax_type.rs
index 50fc1950..20edb827 100644
--- a/oid4vc-core/src/subject_syntax_type.rs
+++ b/oid4vc-core/src/subject_syntax_type.rs
@@ -80,7 +80,7 @@ impl FromStr for DidMethod {
     type Err = serde_json::Error;
 
     fn from_str(s: &str) -> Result<Self, Self::Err> {
-        let mut did_scheme = s.splitn(3, ':');
+        let mut did_scheme = s.splitn(4, ':');
 
         match (
             did_scheme.next(),
@@ -88,6 +88,11 @@ impl FromStr for DidMethod {
             did_scheme.next(),
             did_scheme.next(),
         ) {
+            // (Some("did"), Some(method), Some(submethod), _)
+            //     if !method.is_empty() && !submethod.is_empty() && method.chars().all(char::is_alphanumeric) =>
+            // {
+            //     Ok(DidMethod(format!("{}:{}", method, submethod)))
+            // }
             (Some("did"), Some(method), _, None) if !method.is_empty() && method.chars().all(char::is_alphanumeric) => {
                 Ok(DidMethod(method.to_owned()))
             }
@@ -106,6 +111,11 @@ impl Display for DidMethod {
 mod tests {
     use super::*;
 
+    #[test]
+    fn test() {
+        assert!(DidMethod::from_str("did:example:123").is_err());
+    }
+
     #[test]
     fn test_did_method() {
         assert!(DidMethod::from_str("").is_err());
@@ -114,6 +124,18 @@ mod tests {
         assert!(DidMethod::from_str("invalid:").is_err());
         assert!(DidMethod::from_str("did:example_").is_err());
         assert!(DidMethod::from_str("did:example").is_ok());
+        assert!(DidMethod::from_str("did:example:submethod").is_ok());
+        // assert!(DidMethod::from_str("did:example:submethod:0x123").is_ok());
+
+        assert_eq!(DidMethod::from_str("did:example").unwrap().to_string(), "did:example");
+        assert_eq!(
+            DidMethod::from_str("did:example:submethod").unwrap().to_string(),
+            "did:example:submethod"
+        );
+        assert_eq!(
+            DidMethod::from_str("did:example:submethod:0x123").unwrap().to_string(),
+            "did:example:submethod"
+        );
     }
 
     #[test]