An application is taken when the customer comes to the bank and says "I would like to borrow $xxxx to purchase/do xxxxx" and the bank writes up an approval memo. The bank has to decide when it has an application from the customer: could be when financials are received and sent to credit for analysis, could be when term sheet is accepted and application fee paid, could be as soon as they ask because you already have all current financial information on file.
How quickly you must respond varies with the revenues of the customer. You should review Notifications in Regulation B. (a)(1) and (a)(2) referenced relate to timing of notice (a)(1) and content of notice (a)(2):
(3) Notification to business credit applicants. For business credit, a creditor shall comply with the notification requirements of this section in the following manner:
(i) With regard to a business that had gross revenues of $1 million or less in its preceding fiscal year (other than an extension of trade credit, credit incident to a factoring agreement, or other similar types of business credit), a creditor shall comply with paragraphs (a)(1) and (2) of this section, except that:
(A) The statement of the action taken may be given orally or in writing, when adverse action is taken;
(B) Disclosure of an applicant's right to a statement of reasons may be given at the time of application, instead of when adverse action is taken, provided the disclosure contains the information required by paragraph (a)(2)(ii) of this section and the ECOA notice specified in paragraph (b)(1) of this section;
(C) For an application made entirely by telephone, a creditor satisfies the requirements of paragraph (a)(3)(i) of this section by an oral statement of the action taken and of the applicant's right to a statement of reasons for adverse action.
(ii) With regard to a business that had gross revenues in excess of $1 million in its preceding fiscal year or an extension of trade credit, credit incident to a factoring agreement, or other similar types of business credit, a creditor shall:
(A) Notify the applicant, within a reasonable time, orally or in writing, of the action taken; and
(B) Provide a written statement of the reasons for adverse action and the ECOA notice specified in paragraph (b)(1) of this section if the applicant makes a written request for the reasons within 60 days of the creditor's notification.