diff --git a/package.json b/package.json
index 9dc04b8..be4d6b7 100644
--- a/package.json
+++ b/package.json
@@ -15,7 +15,7 @@
     "test:integration:testnet:local": "RESTURL=http://localhost:4000/v3/ mocha --timeout 30000 test/integration/testnet",
     "test:integration:free": "bash test/integration/test-free-tier.sh",
     "test:integration:free:testnet": "bash test/integration/testnet/test-free-tier.sh",
-    "test:temp": "mocha --timeout 30000 test/integration/slp.js",
+    "test:temp": "mocha --timeout 30000 -g '#tokenUtxoDetails' test/integration/slp.js",
     "test:integration:api": "RESTURL=https://api.fullstack.cash/v3/ mocha --timeout 30000 test/integration",
     "coverage": "nyc report --reporter=text-lcov | coveralls",
     "coverage:report": "nyc --reporter=html mocha --timeout 25000 test/unit/",
diff --git a/src/slp/utils.js b/src/slp/utils.js
index eaed2b9..fb5474d 100644
--- a/src/slp/utils.js
+++ b/src/slp/utils.js
@@ -748,6 +748,7 @@ class Utils {
 
       return tokenData
     } catch (error) {
+      // console.log('decodeOpReturn error: ', error)
       if (error.response && error.response.data) throw error.response.data
       throw error
     }
@@ -870,12 +871,29 @@ class Utils {
           slpData = await this.decodeOpReturn(utxo.txid)
           // console.log(`slpData: ${JSON.stringify(slpData, null, 2)}`)
         } catch (err) {
-          // console.log(`error: `, err)
+          // console.log(`error from decodeOpReturn(${utxo.txid}): `, err)
+
           // An error will be thrown if the txid is not SLP.
-          // Mark as false and continue the loop.
-          // outAry.push(false)
-          utxo.isValid = false
-          outAry.push(utxo)
+          // If error is for some other reason, like a 429 error, mark utxo as 'null'
+          // to display the unknown state.
+          if (
+            !err.message ||
+            err.message.indexOf("scriptpubkey not op_return") === -1
+          ) {
+            // console.log(`error from decodeOpReturn(${utxo.txid}): `, err)
+
+            utxo.isValid = null
+            outAry.push(utxo)
+
+            // If error is thrown because there is no OP_RETURN, then it's not
+            // an SLP UTXO.
+            // Mark as false and continue the loop.
+          } else {
+            utxo.isValid = false
+            outAry.push(utxo)
+          }
+
+          // Halt the execution of the loop and increase to the next index.
           continue
         }
 
diff --git a/test/integration/slp.js b/test/integration/slp.js
index fb691e6..5e81e8e 100644
--- a/test/integration/slp.js
+++ b/test/integration/slp.js
@@ -582,7 +582,7 @@ describe(`#SLP`, () => {
         // console.log(`utxos: ${JSON.stringify(utxos, null, 2)}`)
 
         const result = await bchjs.SLP.Utils.hydrateUtxos(utxos.utxos)
-        // console.log(`result: ${JSON.stringify(result, null, 2)}`)
+        console.log(`result: ${JSON.stringify(result, null, 2)}`)
 
         // Test the general structure of the output.
         assert.isArray(result.slpUtxos)
diff --git a/test/unit/slp-utils.js b/test/unit/slp-utils.js
index 58ffe91..ed1175e 100644
--- a/test/unit/slp-utils.js
+++ b/test/unit/slp-utils.js
@@ -1695,6 +1695,46 @@ describe("#SLP Utils", () => {
 
       assert2.equal(data[2].isValid, false)
     })
+
+    it("should return null value when 429 recieved", async () => {
+      const utxos = [
+        {
+          height: 654522,
+          tx_hash:
+            "072a1e2c2d5f1309bf4eef7f88684e4ecd544a903b386b07f3e04b91b13d8af1",
+          tx_pos: 0,
+          value: 6999,
+          satoshis: 6999,
+          txid:
+            "072a1e2c2d5f1309bf4eef7f88684e4ecd544a903b386b07f3e04b91b13d8af1",
+          vout: 0
+        },
+        {
+          height: 654522,
+          tx_hash:
+            "a72db6a0883ecb8e379f317231b2571e41e041b7b1107e3e54c2e0b3386ac6ca",
+          tx_pos: 1,
+          value: 546,
+          satoshis: 546,
+          txid:
+            "a72db6a0883ecb8e379f317231b2571e41e041b7b1107e3e54c2e0b3386ac6ca",
+          vout: 1
+        }
+      ]
+
+      sandbox.stub(slp.Utils, "decodeOpReturn").rejects({
+        error:
+          "Too many requests. Your limits are currently 3 requests per minute. Increase rate limits at https://fullstack.cash"
+      })
+
+      const data = await slp.Utils.tokenUtxoDetails(utxos)
+      // console.log(`data: ${JSON.stringify(data, null, 2)}`)
+
+      // Values should be 'null' to signal that a determination could not be made
+      // due to a throttling issue.
+      assert.equal(data[0].isValid, null)
+      assert.equal(data[1].isValid, null)
+    })
   })
 
   describe("#txDetails", () => {