Filed by Nuveen Build America Bond Fund
pursuant to Rule 425 under the Securities Act of 1933, as amended,
and deemed filed pursuant to Rule14a-6
under the Securities Exchange Act of 1934, as amended
Subject Company:
Nuveen Build America Bond Opportunity Fund
Commission FileNo. 811-22425
NUVEEN BUILD AMERICA BOND OPPORTUNITY FUND (NBD)
PLEASE VOTE NOW! WE NEED YOUR HELP!
VOTING NOW HELPS LOWER OVERALL PROXY COSTS AND ELIMINATES
FURTHER MAILINGS AND PHONE CALLS
Dear Shareholder:
The Annual Meeting of Nuveen Build America Bond Opportunity Fund has been postponed to allow shareholders more time to vote.The meeting will reconvene on August 22, 2018 at 2:00 p.m., Central Time at the offices of Nuveen, 333 West Wacker Drive, Chicago, IL 60606. We previously sent you a Joint Proxy Statement/Prospectus concerning an important proposal affecting your Fund, which will be considered at the Annual Meeting of Shareholders. The Fund still requires a high level of participation in order to vote on this proposal at the Annual Meeting of Shareholders. This letter was sent because you held shares in the Fund on the record date andwe have not received your vote.
YOUR FUND’S BOARD OF TRUSTEES RECOMMENDS THAT YOU VOTE “FOR” THE PROPOSAL
YOUR VOTE IS VERY IMPORTANT
Your prompt proxy vote willSAVE the cost of sending additional reminder mailings,e-mails and phone calls.
Please vote using one of the following options:
| 1. | VOTE ONLINE |
Log on towww.proxyvote.com or scan the QR code shown on your voting instrument. Please have your voting instrument in hand to access your control number (located in the box) and follow theon-screen instructions.
| 2. | VOTE BY TOUCH-TONE TELEPHONE |
Call the toll free number listed on your voting instrument. Please have your voting instrument in hand to access your control number (located in the box) and follow the recorded instructions.
| 3. | VOTE BY MAIL |
Complete, sign and date your voting instrument and then return it in the enclosed postage paid envelope.
The Joint Proxy Statement/Prospectus we sent you contains important information regarding the proposal that you and other shareholders are being asked to consider. You may obtain a copy of the Joint Proxy Statement/Prospectus for your Fund athttp://www.nuveenproxy.com/Closed-End-Fund-Proxy-Information/. Please read the materials carefully. If you have any questions regarding the proposal, or need assistance with voting, you may call Computershare Fund Services, the Fund’s proxy solicitor, toll free at1-866-963-5818.
Thank you for your prompt attention to this matter. If you have already voted, we appreciate your participation.