diff --git a/src/app/(app)/collection-pool/view-model.test.ts b/src/app/(app)/collection-pool/view-model.test.ts
index b018482..f2d03bc 100644
--- a/src/app/(app)/collection-pool/view-model.test.ts
+++ b/src/app/(app)/collection-pool/view-model.test.ts
@@ -266,6 +266,71 @@ describe("buildVisibleRows sort modes (nearby pinning)", () => {
   });
 });
 
+describe("buildVisibleRows — supplier-first sort (operational mode)", () => {
+  const todayYmd = "2026-07-10";
+
+  it("sorts by supplierName first when sortMode is operational", () => {
+    const rows = buildVisibleRows(
+      [
+        makeRow({ id: "beta", supplierName: "Beta" }),
+        makeRow({ id: "acme", supplierName: "Acme" }),
+        makeRow({ id: "alpha", supplierName: "Alpha" }),
+      ],
+      { todayYmd, searchText: "", readyFilter: "all", sortMode: "operational" },
+    );
+    expect(rows.map((r) => r.id)).toEqual(["acme", "alpha", "beta"]);
+  });
+
+  it("falls through to assignmentState within the same supplier", () => {
+    const rows = buildVisibleRows(
+      [
+        makeRow({
+          id: "acme-unassigned",
+          supplierName: "Acme",
+          item_status: "collection_pool",
+        }),
+        makeRow({
+          id: "acme-today",
+          supplierName: "Acme",
+          item_status: "assigned",
+          drv_id: "drv-1",
+          assigned_at: `${todayYmd}T00:00:00.000Z`,
+        }),
+      ],
+      { todayYmd, searchText: "", readyFilter: "all", sortMode: "operational" },
+    );
+    expect(rows.map((r) => r.id)).toEqual(["acme-today", "acme-unassigned"]);
+  });
+
+  it("nearby mode still uses cluster prefix before supplier", () => {
+    const rows = buildVisibleRows(
+      [
+        makeRow({
+          id: "beta-cluster-a",
+          supplierName: "Beta",
+          clusterSortKey: "cluster-a",
+        }),
+        makeRow({
+          id: "acme-cluster-b",
+          supplierName: "Acme",
+          clusterSortKey: "cluster-b",
+        }),
+        makeRow({
+          id: "acme-cluster-a",
+          supplierName: "Acme",
+          clusterSortKey: "cluster-a",
+        }),
+      ],
+      { todayYmd, searchText: "", readyFilter: "all", sortMode: "nearby" },
+    );
+    expect(rows.map((r) => r.id)).toEqual([
+      "acme-cluster-a",
+      "beta-cluster-a",
+      "acme-cluster-b",
+    ]);
+  });
+});
+
 describe("buildSupplierGroups", () => {
   it("returns an empty array for empty input", () => {
     expect(buildSupplierGroups([], new Map())).toEqual([]);
diff --git a/src/app/(app)/collection-pool/view-model.ts b/src/app/(app)/collection-pool/view-model.ts
index 8faa1d4..cfab542 100644
--- a/src/app/(app)/collection-pool/view-model.ts
+++ b/src/app/(app)/collection-pool/view-model.ts
@@ -109,6 +109,12 @@ export function buildVisibleRows(
         if (clusterDiff !== 0) return clusterDiff;
       }
 
+      // Supplier name is the primary group key. Rows in the same
+      // supplier are then ordered by assignment urgency (today →
+      // unassigned → future), then by updated, then by PO + description.
+      const supplierDiff = (a.supplierName ?? "").localeCompare(b.supplierName ?? "");
+      if (supplierDiff !== 0) return supplierDiff;
+
       const stateDiff =
         ASSIGNMENT_SORT_ORDER[getAssignmentState(a, options.todayYmd)] -
         ASSIGNMENT_SORT_ORDER[getAssignmentState(b, options.todayYmd)];
@@ -118,8 +124,8 @@ export function buildVisibleRows(
       const updatedB = b.updated ?? "";
       if (updatedA !== updatedB) return updatedA.localeCompare(updatedB);
 
-      return `${a.supplierName ?? ""}|${a.poNumber ?? ""}|${a.description ?? ""}`.localeCompare(
-        `${b.supplierName ?? ""}|${b.poNumber ?? ""}|${b.description ?? ""}`,
+      return `${a.poNumber ?? ""}|${a.description ?? ""}`.localeCompare(
+        `${b.poNumber ?? ""}|${b.description ?? ""}`,
       );
     });
 }