diff --git a/src/lib.rs b/src/lib.rs
index 3d1c089..1322eef 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -41,11 +41,18 @@ deposit,1,3,2.0
 withdrawal,1,4,1.5
 withdrawal,2,5,3.0";
 
-            let expected = vec![Transaction {tx_type: TransactionType::Deposit, amount: 10000, client: 1, tx: 1}];
+            let expected = vec![
+            Transaction {tx_type: TransactionType::Deposit, amount: 10000, client: 1, tx: 1},
+            Transaction {tx_type: TransactionType::Deposit, amount: 20000, client: 2, tx: 2},
+            Transaction {tx_type: TransactionType::Deposit, amount: 20000, client: 1, tx: 3},
+            Transaction {tx_type: TransactionType::Withdrawal, amount: 15000, client: 1, tx: 4},
+            Transaction {tx_type: TransactionType::Withdrawal, amount: 30000, client: 2, tx: 5},
+            ];
             let txs = parse(data.as_bytes()).collect::<Vec<Transaction>>().await;
             assert_eq!(expected, txs);
         });
     }
+
     #[test]
     fn valid_csv_with_whitespaces_is_parsed() {
         block_on(async {
@@ -57,9 +64,62 @@ deposit,         1,   3,    2.0
 withdrawal,      1,   4,    1.5
 withdrawal,      2,   5,    3.0";
 
-            let txs = parse(data.as_bytes());
-            let result: Vec<Transaction> = txs.collect::<Vec<Transaction>>().await;
-            result.iter().for_each(|t| eprintln!("{:?}", t));
+            let expected = vec![
+            Transaction {tx_type: TransactionType::Deposit, amount: 10000, client: 1, tx: 1},
+            Transaction {tx_type: TransactionType::Deposit, amount: 20000, client: 2, tx: 2},
+            Transaction {tx_type: TransactionType::Deposit, amount: 20000, client: 1, tx: 3},
+            Transaction {tx_type: TransactionType::Withdrawal, amount: 15000, client: 1, tx: 4},
+            Transaction {tx_type: TransactionType::Withdrawal, amount: 30000, client: 2, tx: 5},
+            ];
+            let txs = parse(data.as_bytes()).collect::<Vec<Transaction>>().await;
+            assert_eq!(expected, txs);
+        });
+    }
+
+    #[test]
+    fn amounts_are_parsed_correctly() {
+        block_on(async {
+            let data = "\
+type,client,tx,amount
+deposit,1,1,1.0001
+deposit,2,2,2.0010
+deposit,1,3,10.01
+withdrawal,1,4,01.10
+withdrawal,2,5,10.0110101";
+
+            let expected = vec![
+            Transaction {tx_type: TransactionType::Deposit, amount: 10001, client: 1, tx: 1},
+            Transaction {tx_type: TransactionType::Deposit, amount: 20010, client: 2, tx: 2},
+            Transaction {tx_type: TransactionType::Deposit, amount: 100100, client: 1, tx: 3},
+            Transaction {tx_type: TransactionType::Withdrawal, amount: 11000, client: 1, tx: 4},
+            Transaction {tx_type: TransactionType::Withdrawal, amount: 100110, client: 2, tx: 5},
+            ];
+            let txs = parse(data.as_bytes()).collect::<Vec<Transaction>>().await;
+            assert_eq!(expected, txs);
+        });
+    }
+
+    #[test]
+    fn invalid_amoutns_are_filtered() {
+        block_on(async {
+            let data = "\
+type,client,tx,amount
+deposit,1,1,99999999999999999
+deposit,2,2,18446744073709551615
+deposit,1,3,18446744073709551616
+withdrawal,1,4,0
+withdrawal,2,5,-1
+withdrawal,1,6,-99999999999999999
+withdrawal,1,6,-18446744073709551615
+withdrawal,1,7,-18446744073709551616";
+
+            let expected = vec![
+            Transaction {tx_type: TransactionType::Withdrawal, amount: 0, client: 1, tx: 4},
+            ];
+            let txs = parse(data.as_bytes()).collect::<Vec<Transaction>>().await;
+            println!("PARSE: {}", "0.1".parse::<f32>().unwrap());
+
+            assert_eq!(expected, txs);
         });
     }
 }
diff --git a/src/types/mod.rs b/src/types/mod.rs
index 895ce1e..908f08f 100644
--- a/src/types/mod.rs
+++ b/src/types/mod.rs
@@ -1,5 +1,6 @@
-use serde::{Deserialize, Deserializer};
 use serde::de;
+use serde::{Deserialize, Deserializer};
+const PRECISION: u32 = 4;
 
 #[derive(Eq, PartialEq, Debug, Deserialize)]
 #[serde(rename_all = "lowercase")]
@@ -12,24 +13,31 @@ pub enum TransactionType {
 pub struct Transaction {
     #[serde(rename = "type")]
     pub tx_type: TransactionType,
-    pub client: usize,
+    pub client: u16,
     pub tx: usize,
     /// Amount of the smallest unit, e.g. 0.0001 as per the specification
     #[serde(deserialize_with = "de_amount")]
     pub amount: usize,
 }
 
-fn de_amount<'de, D>(deserializer: D) -> Result<usize, D::Error> where D: Deserializer<'de> {
+fn de_amount<'de, D>(deserializer: D) -> Result<usize, D::Error>
+where
+    D: Deserializer<'de>,
+{
     //TODO validate for input such as `.100` so it doesn't give 100
     let deserialized = String::deserialize(deserializer)?;
     let mut splitted = deserialized.split('.');
-    let mut ret: usize = 0;
-    let mut factor = 4;
-    while let Some(s) = splitted.next() {
-        ret += s.parse::<usize>().map_err(de::Error::custom)? * 10usize.pow(factor);
-        if factor < 1 { break;} 
-        factor -= 4;
-    };
+    let units = splitted
+        .next()
+        .map_or(Ok(0usize), |v| v.parse::<usize>())
+        .map_err(de::Error::custom)?
+        .checked_mul(10usize.pow(PRECISION))
+        .ok_or_else(|| de::Error::custom("Value too large"))?;
+    //TODO improve this to avoid `format!`
+    let dec = splitted
+        .next()
+        .map_or(Ok(0usize), |v| format!("{:0<4.4}", v).parse::<usize>())
+        .map_err(de::Error::custom)?;
 
-    Ok(ret)
+    Ok(units + dec)
 }