diff --git a/sigmastate/src/main/scala/org/ergoplatform/ErgoBoxCandidate.scala b/sigmastate/src/main/scala/org/ergoplatform/ErgoBoxCandidate.scala
index bf13b8d9c8..9fa6cafaf0 100644
--- a/sigmastate/src/main/scala/org/ergoplatform/ErgoBoxCandidate.scala
+++ b/sigmastate/src/main/scala/org/ergoplatform/ErgoBoxCandidate.scala
@@ -3,7 +3,7 @@ package org.ergoplatform
 import java.util
 import org.ergoplatform.ErgoBox._
 import org.ergoplatform.settings.ErgoAlgos
-import scorex.util.{bytesToId, ModifierId}
+import scorex.util.{ModifierId, bytesToId}
 import sigmastate.Values._
 import sigmastate._
 import sigmastate.SType.AnyOps
@@ -16,7 +16,7 @@ import sigmastate.serialization.ErgoTreeSerializer.DefaultSerializer
 import sigmastate.util.safeNewArray
 import spire.syntax.all.cfor
 
-import scala.collection.immutable
+import scala.collection.{immutable, mutable}
 import scala.runtime.ScalaRunTime
 
 /**
@@ -100,12 +100,17 @@ class ErgoBoxCandidate(val value: Long,
     s"tokens: (${additionalTokens.map(t => ErgoAlgos.encode(t._1) + ":" + t._2).toArray.mkString(", ")}), " +
     s"$additionalRegisters, creationHeight: $creationHeight)"
 
-  /** Additional tokens stored in the box. */
-  lazy val tokens: Map[ModifierId, Long] =
-    additionalTokens
-      .toArray
-      .map(t => bytesToId(t._1) -> t._2)
-      .toMap
+  /** Additional tokens stored in the box, merged into a Map.
+    * This method is not used in ErgoTree and serialization, not part of consensus.
+    */
+  lazy val tokens: Map[ModifierId, Long] = {
+    val merged = new mutable.HashMap[ModifierId, Long]
+    additionalTokens.foreach { case (id, amount) =>
+      val mId = bytesToId(id)
+      merged.put(mId, java7.compat.Math.addExact(merged.getOrElse(mId, 0L), amount))
+    }
+    merged.toMap
+  }
 }
 
 object ErgoBoxCandidate {
diff --git a/sigmastate/src/test/scala/org/ergoplatform/ErgoLikeTransactionSpec.scala b/sigmastate/src/test/scala/org/ergoplatform/ErgoLikeTransactionSpec.scala
index ab27179bec..5de774def8 100644
--- a/sigmastate/src/test/scala/org/ergoplatform/ErgoLikeTransactionSpec.scala
+++ b/sigmastate/src/test/scala/org/ergoplatform/ErgoLikeTransactionSpec.scala
@@ -46,6 +46,7 @@ class ErgoLikeTransactionSpec extends SigmaDslTesting {
       100,
       Coll(
         Digest32 @@ (ErgoAlgos.decodeUnsafe(token1)) -> 10000000L,
+        Digest32 @@ (ErgoAlgos.decodeUnsafe(token1)) -> 500L,
         Digest32 @@ (ErgoAlgos.decodeUnsafe(token2)) -> 500L
       )
     )
@@ -70,6 +71,7 @@ class ErgoLikeTransactionSpec extends SigmaDslTesting {
     b1.tokens shouldBe expectedTokens
     b1_clone.tokens shouldBe expectedTokens
     b3.tokens shouldBe expectedTokens
+    b2.tokens shouldBe Map[ModifierId, Long](ModifierId @@ token1 -> 10000500L, ModifierId @@ token2 -> 500L)
 
     assertResult(true)(b1.hashCode() == b1.hashCode())
     assertResult(true)(b1 == b1)