diff --git a/web/src/components/CompanyFilterDropdown.tsx b/web/src/components/CompanyFilterDropdown.tsx
new file mode 100644
index 0000000..958d894
--- /dev/null
+++ b/web/src/components/CompanyFilterDropdown.tsx
@@ -0,0 +1,50 @@
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuTrigger,
+  DropdownMenuCheckboxItem,
+} from "./ui/dropdown-menu";
+import { Button } from "./ui/button";
+import { ChevronDown } from "lucide-react";
+
+type Props = {
+  allCompanies: string[];
+  selectedCompanies: string[];
+  setSelectedCompanies: React.Dispatch<React.SetStateAction<string[]>>;
+};
+
+export function CompanyFilterDropdown({
+  allCompanies,
+  selectedCompanies,
+  setSelectedCompanies,
+}: Props) {
+  function toggleCompany(name: string) {
+    setSelectedCompanies((prev) =>
+      prev.includes(name) ? prev.filter((n) => n !== name) : [...prev, name],
+    );
+  }
+
+  return (
+    <DropdownMenu>
+      <DropdownMenuTrigger asChild>
+        <Button variant="outline" className="shadow-none" size="sm">
+          Company
+          {selectedCompanies.length > 0 && ` (${selectedCompanies.length})`}
+          <ChevronDown />
+        </Button>
+      </DropdownMenuTrigger>
+      <DropdownMenuContent className="max-h-72 w-48 overflow-y-auto bg-[#101010]" align="start">
+        {allCompanies.map((name) => (
+          <DropdownMenuCheckboxItem
+            key={name}
+            checked={selectedCompanies.includes(name)}
+            onCheckedChange={() => toggleCompany(name)}
+            onSelect={(e) => e.preventDefault()}
+          >
+            {name}
+          </DropdownMenuCheckboxItem>
+        ))}
+      </DropdownMenuContent>
+    </DropdownMenu>
+  );
+}
diff --git a/web/src/pages/AllProblems.tsx b/web/src/pages/AllProblems.tsx
index 9d793a7..b68a6fd 100644
--- a/web/src/pages/AllProblems.tsx
+++ b/web/src/pages/AllProblems.tsx
@@ -19,6 +19,7 @@ import { getCompanyColor } from "~/utils/companyColors";
 import { cn } from "~/lib/utils";
 import { Separator } from "~/components/ui/separator";
 import { TagFilterDropdown } from "~/components/TagFilterDropdown";
+import { CompanyFilterDropdown } from "~/components/CompanyFilterDropdown";
 
 ModuleRegistry.registerModules([AllCommunityModule]);
 
@@ -372,6 +373,17 @@ export default function AllProblems() {
 
   const [hideCompleted, setHideCompleted] = useState(false);
 
+  const [selectedCompanies, setSelectedCompanies] = useState<string[]>([]);
+
+  // ponytail: compute unique companies from loaded data, no extra query
+  const allCompanies = useMemo(() => {
+    const names = new Set<string>();
+    for (const p of problems) {
+      for (const c of p.other_companies) names.add(c);
+    }
+    return [...names].sort();
+  }, [problems]);
+
   const gridRef = useRef<AgGridReact<Problem>>(null);
 
   // fetch
@@ -451,11 +463,11 @@ export default function AllProblems() {
     // AG Grid external filter handles difficulty; quick filter handles search
     gridRef.current.api.setGridOption("quickFilterText", search);
     gridRef.current.api.onFilterChanged();
-  }, [search, diffFilter, selectedTags, tagMatchMode, hideCompleted]);
+  }, [search, diffFilter, selectedTags, tagMatchMode, hideCompleted, selectedCompanies]);
 
   const isExternalFilterPresent = useCallback(() => {
-    return diffFilter !== "All" || selectedTags.length > 0 || hideCompleted;
-  }, [diffFilter, selectedTags, hideCompleted]);
+    return diffFilter !== "All" || selectedTags.length > 0 || hideCompleted || selectedCompanies.length > 0;
+  }, [diffFilter, selectedTags, hideCompleted, selectedCompanies]);
 
   const doesExternalFilterPass = useCallback(
     (node: { data?: Problem }) => {
@@ -489,9 +501,18 @@ export default function AllProblems() {
         }
       }
 
+      // Company filter — match any selected company
+      if (selectedCompanies.length > 0) {
+        const problemCompanies = problem.other_companies ?? [];
+        const matchesCompany = selectedCompanies.some((c) =>
+          problemCompanies.includes(c),
+        );
+        if (!matchesCompany) return false;
+      }
+
       return true;
     },
-    [diffFilter, selectedTags, tagMatchMode, hideCompleted],
+    [diffFilter, selectedTags, tagMatchMode, hideCompleted, selectedCompanies],
   );
 
   /* --------------------- Column Defs -------------------- */
@@ -693,6 +714,12 @@ export default function AllProblems() {
               tagMatchMode={tagMatchMode}
               setTagMatchMode={setTagMatchMode}
             />
+
+            <CompanyFilterDropdown
+              allCompanies={allCompanies}
+              selectedCompanies={selectedCompanies}
+              setSelectedCompanies={setSelectedCompanies}
+            />
           </div>
         </div>
       </div>