diff --git a/quimb/tensor/decomp.py b/quimb/tensor/decomp.py
index 93a08eb5..cc8186a4 100644
--- a/quimb/tensor/decomp.py
+++ b/quimb/tensor/decomp.py
@@ -185,6 +185,18 @@ def _trim_and_renorm_svd_result(
     return U, None, VH
 
 
+@compose
+def identity(x, **kwargs):
+    """
+    No-op "decomposition" that leaves the input unchanged. Can be useful to quickly build a tensor network representing a given tensor "as is".
+    """
+
+    if x.shape[0] < x.shape[1]:
+        return do("eye", x.shape[0], like=x), None, x
+    else:
+        return x, None, do("eye", x.shape[1], like=x)
+
+
 @compose
 def svd_truncated(
     x,
diff --git a/quimb/tensor/tensor_core.py b/quimb/tensor/tensor_core.py
index 39f6d7a6..5efe6255 100644
--- a/quimb/tensor/tensor_core.py
+++ b/quimb/tensor/tensor_core.py
@@ -325,6 +325,7 @@ def rand_uuid(base=""):
 
 _VALID_SPLIT_GET = {None, "arrays", "tensors", "values"}
 _SPLIT_FNS = {
+    "identity": decomp.identity,
     "svd": decomp.svd_truncated,
     "eig": decomp.svd_via_eig_truncated,
     "lu": decomp.lu_truncated,