diff --git a/AssetManager.Data/Repositories/MarketDataRepository.cs b/AssetManager.Data/Repositories/MarketDataRepository.cs
index 32b2ed8..6a1d20c 100644
--- a/AssetManager.Data/Repositories/MarketDataRepository.cs
+++ b/AssetManager.Data/Repositories/MarketDataRepository.cs
@@ -86,8 +86,9 @@ public class MarketDataRepository : IMarketDataRepository
 
     public async Task<List<TiingoTicker>> SearchTiingoTickersAsync(string keyword, int limit)
     {
+        var keywordUpper = keyword.ToUpper();
         return await _db.Queryable<TiingoTicker>()
-            .Where(t => t.Ticker.Contains(keyword.ToUpper()) || 
+            .Where(t => t.Ticker != null && t.Ticker.Contains(keywordUpper) || 
                         (t.Name != null && t.Name.Contains(keyword)))
             .Take(limit)
             .ToListAsync();
diff --git a/AssetManager.Data/Repositories/PortfolioRepository.cs b/AssetManager.Data/Repositories/PortfolioRepository.cs
index b56d1e8..d91e94a 100644
--- a/AssetManager.Data/Repositories/PortfolioRepository.cs
+++ b/AssetManager.Data/Repositories/PortfolioRepository.cs
@@ -131,20 +131,20 @@ public class PortfolioRepository : IPortfolioRepository
 
         if (startDate.HasValue)
         {
-            query = query.Where(n => n.Date >= startDate.Value.Date);
+            query = query.Where(n => n.NavDate >= startDate.Value.Date);
         }
         if (endDate.HasValue)
         {
-            query = query.Where(n => n.Date <= endDate.Value.Date);
+            query = query.Where(n => n.NavDate <= endDate.Value.Date);
         }
 
-        return await query.OrderBy(n => n.Date).ToListAsync();
+        return await query.OrderBy(n => n.NavDate).ToListAsync();
     }
 
     public async Task<int> DeleteNavHistoryAfterDateAsync(string portfolioId, DateTime date)
     {
         return await _db.Deleteable<PortfolioNavHistory>()
-            .Where(n => n.PortfolioId == portfolioId && n.Date >= date.Date)
+            .Where(n => n.PortfolioId == portfolioId && n.NavDate >= date.Date)
             .ExecuteCommandAsync();
     }