diff --git a/crates/uplc/src/machine/value.rs b/crates/uplc/src/machine/value.rs
index 7afa756e..09dbb566 100644
--- a/crates/uplc/src/machine/value.rs
+++ b/crates/uplc/src/machine/value.rs
@@ -398,9 +398,7 @@ pub fn from_pallas_bigint(n: &pallas::BigInt) -> BigInt {
     match n {
         pallas::BigInt::Int(i) => i128::from(*i).into(),
         pallas::BigInt::BigUInt(bytes) => BigInt::from_bytes_be(num_bigint::Sign::Plus, bytes),
-        pallas::BigInt::BigNInt(bytes) => {
-            BigInt::from_bytes_be(num_bigint::Sign::Minus, bytes) - 1
-        },
+        pallas::BigInt::BigNInt(bytes) => BigInt::from_bytes_be(num_bigint::Sign::Minus, bytes) - 1,
     }
 }
 
diff --git a/crates/uplc/src/parser.rs b/crates/uplc/src/parser.rs
index 23a564b6..2effdcf7 100644
--- a/crates/uplc/src/parser.rs
+++ b/crates/uplc/src/parser.rs
@@ -4,12 +4,11 @@ use crate::{
     ast::{Constant, Name, Program, Term, Type},
     builtins::DefaultFunction,
     machine::runtime::Compressable,
+    machine::value::to_pallas_bigint,
 };
 
 use interner::Interner;
 use num_bigint::BigInt;
-use num_bigint::Sign;
-use num_traits::ToPrimitive;
 use pallas_primitives::alonzo::PlutusData;
 use peg::{error::ParseError, str::LineCol};
 
@@ -253,16 +252,7 @@ peg::parser! {
             PlutusData::Map(pallas_codec::utils::KeyValuePairs::Def(kvps))
           }
           / _* "List" _+ ls:plutus_list() { PlutusData::Array(ls) }
-          / _* "I" _+ n:big_number() { match n.to_i64() {
-            Some(n) => PlutusData::BigInt(pallas_primitives::alonzo::BigInt::Int(n.into())),
-            None => match n.sign() {
-              Sign::Minus => {
-                    let m: BigInt = n+1;
-                    PlutusData::BigInt(pallas_primitives::babbage::BigInt::BigNInt(m.to_bytes_be().1.into()))
-                },
-              _ => PlutusData::BigInt(pallas_primitives::babbage::BigInt::BigUInt(n.to_bytes_be().1.into()))
-            }
-          } }
+          / _* "I" _+ n:big_number() { PlutusData::BigInt(to_pallas_bigint(&n)) }
           / _* "B" _+ "#" i:ident()* {?
             Ok(PlutusData::BoundedBytes(
               hex::decode(String::from_iter(i)).or(Err("bytes"))?.into()
diff --git a/crates/uplc/src/pretty.rs b/crates/uplc/src/pretty.rs
index 119bb15e..3493d4e1 100644
--- a/crates/uplc/src/pretty.rs
+++ b/crates/uplc/src/pretty.rs
@@ -2,6 +2,7 @@ use crate::{
     ast::{Constant, Program, Term, Type},
     flat::Binder,
     machine::runtime::Compressable,
+    machine::value::from_pallas_bigint,
 };
 use pallas_primitives::babbage::{Constr, PlutusData};
 use pretty::RcDoc;
@@ -336,11 +337,9 @@ impl Constant {
                     RcDoc::text(", "),
                 ))
                 .append(RcDoc::text("]")),
-            PlutusData::BigInt(bi) => RcDoc::text("I").append(RcDoc::space()).append(match bi {
-                pallas_primitives::babbage::BigInt::Int(v) => RcDoc::text(v.to_string()),
-                pallas_primitives::babbage::BigInt::BigUInt(v) => RcDoc::text(v.to_string()),
-                pallas_primitives::babbage::BigInt::BigNInt(v) => RcDoc::text(v.to_string()),
-            }),
+            PlutusData::BigInt(bi) => RcDoc::text("I")
+                .append(RcDoc::space())
+                .append(RcDoc::text(from_pallas_bigint(bi).to_string())),
             PlutusData::BoundedBytes(bs) => RcDoc::text("B")
                 .append(RcDoc::space())
                 .append(RcDoc::text("#"))