First Trust Nasdaq Artificial Intelligence and Robotics ETF (ROBT) Exchange: NASDAQ

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in common stocks and depositary receipts that comprise the Index. The Index is designed to track the performance of companies engaged in the artificial intelligence ("AI") and robotics segments of the technology, industrial and other economic sectors.The Fund, using an indexing investment approach, attempts to replicate, before fees and expenses, the performance of the Index. First Trust Advisors L.P., the Fund's investment advisor, seeks a correlation of 0.95 or better (before fees and expenses) between the Fund's performance and the performance of the Index; a figure of 1.00 would represent perfect correlation.The Index is owned by Nasdaq, Inc. (the "Index Provider"). The Index Provider and the Consumer Technology Association ("CTA") have jointly developed the eligibility and selection criteria and rules for the Index. The Index Provider also calculates and maintains the Index. The Index includes companies in AI or robotics that are classified as one of the following three groups: Engagers: companies that design, create, integrate, or deliver robotics and/or AI in the form of products, software, or systems; Enablers: companies that develop the building block components for robotics or AI, such as advanced machinery, semiconductors and databases used for machine learning; andEnhancers: companies that provide their own value-added services on top of Engagers, but are not core to their product or service offering.Securities are selected for inclusion in the Index in the following manner:1.the starting universe consists of companies listed on an Index-eligible global stock exchange (see 2.iv. below) classified as AI or robotics engagers, enablers or enhancers, as determined by CTA;2.companies that do not meet minimum liquidity and eligibility requirements, including the following, are excluded:i.minimum worldwide market capitalization of $250 million;ii.minimum three-month average daily dollar trading volume of $3 million;iii.minimum free float of 20%;iv.securities not listed on an Index-eligible global stock exchange (a global exchange will be deemed ineligible if securities cannot be readily obtained either due to foreign investment restrictions or otherwise);3.each remaining company is ranked by its CTA AI/Robotics Exposure Score, which measures the percent a company is exposed to the AI/Robotics sector within its respective engager, enabler or enhancer category (see "Index Information" for a discussion of how Exposure Scores are calculated);4.the Index then selects the top 30 companies within each category, including ties, based on their CTA AI/Robotics Exposure Scores;5.the index divides the overall portfolio weight between the three classifications as follows:i.Engagers: 60%;ii.Enablers: 25%;iii.Enhancers: 15%;6.companies are equally weighted within their respective classifications.The Fund generally will invest in all of the securities comprising the Index, in proportion to their weightings in the Index. Additional minimum eligibility requirements and other information regarding the Index is described in this prospectus under "Index Information."As of January 24, 2018, the Index was comprised of 88 U.S. and foreign common stocks traded on U.S. and non-U.S. exchanges, including American Depository Receipts ("ADRs") and European Depository Receipts ("EDRs") with market capitalizations ranging from $1.2 billion to $886.2 billion. As of January 24, 2018, the Fund had significant investments in Japan and in industrials and information technology companies. The Fund may invest in securities issued by companies operating in emerging markets. The Index Provider classifies a country as "emerging" based on a number of criteria including national income per capita, national market capitalization and national trading volume. Emerging markets are generally characterized by lower market efficiency and less strict standards in accounting and securities regulation than developed markets. Companies are classified as operating in a country primarily by their country of incorporation, domicile and primary exchange listing.The Index Provider reconstitutes the Index components semi-annually in March and September of each year for eligibility, using market data through the end of January and July. Eligible securities for the Index are identified as such using the eligibility criteria set forth in this prospectus under "Index Information." The Index is rebalanced quarterly. Rebalancing is effective as of the market close of the third Friday in February, May, August and November. The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to ensure Index integrity. Ordinarily, a security will be removed from the Index at its last sale price.