As filed with the Securities and Exchange Commission on January 13, 2015

Registration No. 333-200081

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

PRE-EFFECTIVE AMENDMENT NO. 3

TO

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

County Bancorp, Inc.

(Exact Name of Registrant as Specified in Its Charter)

860 North Rapids Road

Manitowoc, Wisconsin 54221-0700

(920) 686-9998

(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant’s Principal Executive Offices)

Timothy J. Schneider

President

860 North Rapids Road

Manitowoc, Wisconsin 54221-0700

(920) 686-9998

(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service)

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after this registration statement becomes effective.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box:  x

If this Form is filed to register additional shares for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering:  ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering:  ¨

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering:  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

The registrant hereby amends this registration statement on such date or dates as may be necessary to delay its effective date until the registrant shall file a further amendment which specifically states that this registration statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the registration statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

EXPLANATORY NOTE

This Amendment No. 3 is being filed solely for the purposes of updating Exhibit 5.1 and the Index to Exhibits herewith. No changes or additions are being made hereby to the Prospectus constituting Part I of the Registration Statement (not included herein) or to Items 13, 14, 15 or 17 of Part II of the Registration Statement.

PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

The exhibits and financial statement schedules filed as part of this registration statement are as follows:

See the Exhibit Index attached to this registration statement, which is incorporated by reference herein.

No financial statement schedules are filed because the required information is not applicable or is included in the consolidated financial statements or related notes.

Signatures

Pursuant to the requirements of the Securities Act of 1933, as amended, the registrant has duly caused this pre-effective Amendment No. 3 to be signed on its behalf by the undersigned, thereunto duly authorized in the City of Manitowoc, State of Wisconsin, on January 13, 2015.

Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed by the following persons in the capacities and on the dates indicated.

* Pursuant to authority granted by powers of attorney, copies of which are filed herewith.

EXHIBIT INDEX