diff --git a/src/bank_header.F90 b/src/bank_header.F90
index 233ff611d4..10c803d60a 100644
--- a/src/bank_header.F90
+++ b/src/bank_header.F90
@@ -15,6 +15,7 @@ module bank_header
      sequence
 
      integer(8) :: id     ! Unique ID
+     real(8)    :: wgt    ! weight of bank site
      real(8)    :: xyz(3) ! location of bank particle
      real(8)    :: uvw(3) ! diretional cosines
      real(8)    :: E      ! energy
diff --git a/src/initialize.F90 b/src/initialize.F90
index c119cd9bab..2f50cf93dd 100644
--- a/src/initialize.F90
+++ b/src/initialize.F90
@@ -149,9 +149,9 @@ contains
   subroutine setup_mpi()
 
 #ifdef MPI
-    integer        :: bank_blocks(4) ! Count for each datatype
-    integer        :: bank_types(4)  ! Datatypes
-    integer(MPI_ADDRESS_KIND) :: bank_disp(4)   ! Displacements
+    integer        :: bank_blocks(5) ! Count for each datatype
+    integer        :: bank_types(5)  ! Datatypes
+    integer(MPI_ADDRESS_KIND) :: bank_disp(5)   ! Displacements
     type(Bank)     :: b
 
     mpi_enabled = .true.
@@ -186,17 +186,18 @@ contains
 
     ! Determine displacements for MPI_BANK type
     call MPI_GET_ADDRESS(b % id,  bank_disp(1), mpi_err)
-    call MPI_GET_ADDRESS(b % xyz, bank_disp(2), mpi_err)
-    call MPI_GET_ADDRESS(b % uvw, bank_disp(3), mpi_err)
-    call MPI_GET_ADDRESS(b % E,   bank_disp(4), mpi_err)
+    call MPI_GET_ADDRESS(b % wgt, bank_disp(2), mpi_err)
+    call MPI_GET_ADDRESS(b % xyz, bank_disp(3), mpi_err)
+    call MPI_GET_ADDRESS(b % uvw, bank_disp(4), mpi_err)
+    call MPI_GET_ADDRESS(b % E,   bank_disp(5), mpi_err)
 
     ! Adjust displacements 
     bank_disp = bank_disp - bank_disp(1)
     
     ! Define MPI_BANK for fission sites
-    bank_blocks = (/ 1, 3, 3, 1 /)
-    bank_types = (/ MPI_INTEGER8, MPI_REAL8, MPI_REAL8, MPI_REAL8 /)
-    call MPI_TYPE_CREATE_STRUCT(4, bank_blocks, bank_disp, & 
+    bank_blocks = (/ 1, 1, 3, 3, 1 /)
+    bank_types = (/ MPI_INTEGER8, MPI_REAL8, MPI_REAL8, MPI_REAL8, MPI_REAL8 /)
+    call MPI_TYPE_CREATE_STRUCT(5, bank_blocks, bank_disp, & 
          bank_types, MPI_BANK, mpi_err)
     call MPI_TYPE_COMMIT(MPI_BANK, mpi_err)
 
diff --git a/src/physics.F90 b/src/physics.F90
index ca9d389ec1..00c2508ce4 100644
--- a/src/physics.F90
+++ b/src/physics.F90
@@ -906,6 +906,9 @@ contains
        fission_bank(i) % id  = p % id
        fission_bank(i) % xyz = p % coord0 % xyz
 
+       ! Set weight of fission bank site
+       fission_bank(i) % wgt = ONE
+
        ! sample cosine of angle
        mu = sample_angle(rxn, E)
 
diff --git a/src/source.F90 b/src/source.F90
index 81d6ab2e6d..654da57af5 100644
--- a/src/source.F90
+++ b/src/source.F90
@@ -94,6 +94,9 @@ contains
              id = bank_first + j - 1
              source_bank(j) % id = id
 
+             ! Set weight to one
+             source_bank(j) % wgt = ONE
+
              ! initialize random number seed
              call set_particle_seed(id)
 
@@ -148,6 +151,8 @@ contains
     src => source_bank(index_source)
 
     ! copy attributes from source bank site
+    p % wgt         = src % wgt
+    p % last_wgt    = src % wgt
     p % coord % xyz = src % xyz
     p % coord % uvw = src % uvw
     p % last_xyz    = src % xyz
@@ -315,7 +320,7 @@ contains
        call fatal_error()
     end if
 
-    ! Read position, angle, and energy
+    ! Read source sites
     read(UNIT=UNIT_SOURCE) source_bank(1:work)
 
     ! Close binary source file