diff --git a/SPARC/api.py b/SPARC/api.py
index a42ddd7..cf053e8 100644
--- a/SPARC/api.py
+++ b/SPARC/api.py
@@ -12,10 +12,10 @@ from typing import TYPE_CHECKING, Annotated, List
 if TYPE_CHECKING:
     from SPARC.database import DatabaseClient
 
-from fastapi import BackgroundTasks, Depends, FastAPI, HTTPException, Query, Request
+from fastapi import BackgroundTasks, Depends, FastAPI, HTTPException, Path, Query, Request
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import JSONResponse, StreamingResponse
-from pydantic import BaseModel, EmailStr, Field
+from pydantic import BaseModel, EmailStr, Field, StringConstraints
 from slowapi import Limiter
 from slowapi.errors import RateLimitExceeded
 from slowapi.util import get_remote_address
@@ -36,6 +36,16 @@ from SPARC.auth import (
 )
 from SPARC.types import BatchAnalysisResult, CompanyAnalysisResult
 
+# Validated company name type: 2-100 chars, alphanumeric + spaces/hyphens/ampersands/periods only.
+CompanyName = Annotated[
+    str,
+    StringConstraints(
+        min_length=2,
+        max_length=100,
+        pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$",
+    ),
+]
+
 
 # Pydantic models for API
 class CompanyAnalysisResponse(BaseModel):
@@ -72,7 +82,7 @@ class CompanyAnalysisRequest(BaseModel):
 class BatchAnalysisRequest(BaseModel):
     """Request model for batch company analysis."""
 
-    companies: list[str] = Field(
+    companies: list[CompanyName] = Field(
         ..., min_length=1, max_length=20, description="List of company names to analyze"
     )
     max_workers: int = Field(
@@ -405,7 +415,7 @@ async def delete_user(
 class TrackCompanyRequest(BaseModel):
     """Request to add a company to tracking."""
 
-    company_name: str = Field(..., min_length=1, max_length=255)
+    company_name: CompanyName = Field(...)
 
 
 @app.get("/admin/tracked", tags=["Admin"])
@@ -432,7 +442,7 @@ async def add_tracked_company(
 
 @app.delete("/admin/tracked/{company_name}", tags=["Admin"])
 async def remove_tracked_company(
-    company_name: str,
+    company_name: Annotated[str, Path(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$")],
     _: UserResponse = Depends(get_current_admin),
 ):
     """Remove a company from the tracked list (admin only)."""
@@ -590,7 +600,7 @@ async def get_analytics_trends(
 
 @app.get("/export/{company_name}", tags=["Export"])
 async def export_company_csv(
-    company_name: str,
+    company_name: Annotated[str, Path(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$")],
     _: UserResponse = Depends(get_current_user),
 ):
     """Export analysis results for a company as a CSV file.
@@ -642,7 +652,7 @@ async def export_company_csv(
 
 @app.get("/export/{company_name}/pdf", tags=["Export"])
 async def export_company_pdf(
-    company_name: str,
+    company_name: Annotated[str, Path(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$")],
     _: UserResponse = Depends(get_current_user),
 ):
     """Export analysis results for a company as a formatted PDF report.
@@ -816,7 +826,7 @@ async def health_check():
     tags=["Analysis"],
 )
 async def analyze_company(
-    company_name: str,
+    company_name: Annotated[str, Path(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$")],
     model: str | None = Query(default=None, description="LLM model to use (e.g. 'openai/gpt-4o'). Defaults to server config."),
     _: UserResponse = Depends(get_current_user),
 ):
@@ -846,7 +856,7 @@ async def analyze_company(
 )
 async def analyze_single_patent(
     patent_id: str,
-    company_name: str = Query(description="Company name for analysis context"),
+    company_name: Annotated[str, Query(min_length=2, max_length=100, pattern=r"^[a-zA-Z0-9][a-zA-Z0-9 \-&.]*$", description="Company name for analysis context")],
     _: UserResponse = Depends(get_current_user),
 ):
     """Analyze a single patent by its publication ID.
diff --git a/tests/test_company_name_validation.py b/tests/test_company_name_validation.py
new file mode 100644
index 0000000..3e6855f
--- /dev/null
+++ b/tests/test_company_name_validation.py
@@ -0,0 +1,157 @@
+"""Tests for company name input validation on analysis endpoints."""
+
+from datetime import datetime
+from unittest.mock import Mock
+
+import pytest
+from fastapi.testclient import TestClient
+
+from SPARC.api import app
+from SPARC.types import CompanyAnalysisResult
+
+
+@pytest.fixture
+def client():
+    """Create test client."""
+    return TestClient(app)
+
+
+@pytest.fixture
+def mock_analyzer(mocker):
+    """Mock the global analyzer so valid requests succeed."""
+    mock = Mock()
+    mock._analyze_company_safe.return_value = CompanyAnalysisResult(
+        company_name="nvidia",
+        analysis="Test analysis",
+        patent_count=1,
+        success=True,
+        timestamp=datetime.now(),
+    )
+    mocker.patch("SPARC.api._analyzer", mock)
+    return mock
+
+
+class TestCompanyNameValidation:
+    """Test that company names are validated on analysis endpoints."""
+
+    # --- Too short ---
+
+    def test_single_char_rejected(self, client, mock_analyzer):
+        """A one-character company name should be rejected."""
+        response = client.get("/analyze/X")
+        assert response.status_code == 422
+
+    # --- Too long ---
+
+    def test_over_100_chars_rejected(self, client, mock_analyzer):
+        """A company name longer than 100 characters should be rejected."""
+        long_name = "A" * 101
+        response = client.get(f"/analyze/{long_name}")
+        assert response.status_code == 422
+
+    # --- Special characters ---
+
+    @pytest.mark.parametrize(
+        "bad_name",
+        [
+            "nvidia!",
+            "intel@corp",
+            "test#company",
+            "foo$bar",
+            "a%b",
+            "x^y",
+            "semi;colon",
+            "drop'table",
+            'say"hello',
+            "path/traversal",
+            "back\\slash",
+            "pipe|char",
+            "star*glob",
+            "question?mark",
+            "<script>",
+            "curly{brace}",
+            "equal=sign",
+            "plus+plus",
+            "comma,separated",
+        ],
+    )
+    def test_special_chars_rejected(self, client, mock_analyzer, bad_name):
+        """Company names with disallowed special characters should be rejected."""
+        response = client.get(f"/analyze/{bad_name}")
+        assert response.status_code == 422
+
+    # --- Valid names ---
+
+    @pytest.mark.parametrize(
+        "valid_name",
+        [
+            "nvidia",
+            "Intel",
+            "TSMC",
+            "Texas Instruments",
+            "Johnson-Johnson",
+            "AT&T",
+            "St. Jude Medical",
+            "3M",
+            "21st Century Fox",
+            "ab",  # minimum length
+            "A" * 100,  # maximum length
+        ],
+    )
+    def test_valid_names_accepted(self, client, mock_analyzer, valid_name):
+        """Valid company names should be accepted (200, not 422)."""
+        response = client.get(f"/analyze/{valid_name}")
+        # Should not be a validation error; 200 or other non-422 status is fine
+        assert response.status_code != 422
+
+    # --- Batch endpoint validation ---
+
+    def test_batch_too_short_rejected(self, client, mock_analyzer):
+        """Batch endpoint should reject company names that are too short."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": ["X"]},
+        )
+        assert response.status_code == 422
+
+    def test_batch_too_long_rejected(self, client, mock_analyzer):
+        """Batch endpoint should reject company names that are too long."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": ["A" * 101]},
+        )
+        assert response.status_code == 422
+
+    def test_batch_special_chars_rejected(self, client, mock_analyzer):
+        """Batch endpoint should reject company names with special chars."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": ["nvidia!", "intel"]},
+        )
+        assert response.status_code == 422
+
+    def test_batch_valid_names_accepted(self, client, mock_analyzer):
+        """Batch endpoint should accept valid company names."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": ["nvidia", "Intel", "AT&T"]},
+        )
+        assert response.status_code != 422
+
+    # --- Name must start with alphanumeric ---
+
+    def test_leading_space_rejected(self, client, mock_analyzer):
+        """Company name starting with a space should be rejected."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": [" nvidia"]},
+        )
+        assert response.status_code == 422
+
+    def test_leading_hyphen_rejected(self, client, mock_analyzer):
+        """Company name starting with a hyphen should be rejected."""
+        response = client.post(
+            "/analyze/batch",
+            json={"companies": ["-nvidia"]},
+        )
+        assert response.status_code == 422