diff --git a/src/services/search/alphabetical-search/service.ts b/src/services/search/alphabetical-search/service.ts
index 74616d21..a15131ad 100644
--- a/src/services/search/alphabetical-search/service.ts
+++ b/src/services/search/alphabetical-search/service.ts
@@ -5,7 +5,7 @@ import Resource from "../../resource";
 export default class AlphabeticalSearchService {
     constructor (private readonly client: IHttpClient) { }
     public async getCompanies (companyName: string, requestId: string,
-        searchBefore: string | null, searchAfter: string | null, size: number | null): Promise<Resource<CompaniesResource>> {
+        searchBefore?: string, searchAfter?: string, size?: number): Promise<Resource<CompaniesResource>> {
         const SEARCH_BEFORE_QUERY = "&search_before=";
         const SEARCH_AFTER_QUERY = "&search_after=";
         const SIZE_QUERY = "&size=";