MicroSectors U.S. Big Banks Index 2X Leveraged ETNs (BNKO) are exchange traded notes issued by Bank of Montreal that provide two times the daily performance of the Solactive MicroSectors U.S. Big Banks Index, less fees. The underlying index, created by Solactive AG in 2019, tracks an equal-dollar weighted portfolio of the 10 largest U.S. banks and financial services companies, including JPMorgan Chase & Co., Bank of America Corp., Wells Fargo & Co., Citigroup Inc., Goldman Sachs Group Inc., Morgan Stanley, PNC Financial Services Group, U.S. Bancorp, Bank of New York Mellon Corp., and Charles Schwab Corp.; the index rebalances monthly to maintain equal 10% weights per constituent. BNKO trades on NYSE Arca under ticker BNKO with CUSIP 63679799, issued on April 5, 2019, with maturity on March 25, 2039, and approximately 500,000 ETNs outstanding as of late 2025. The ETNs offer leveraged exposure to the U.S. banking sector for sophisticated investors seeking amplified daily returns from these major financial institutions, primarily targeted at institutional and retail traders focused on sector-specific strategies. In recent developments, Bank of Montreal announced reverse splits for multiple MicroSectors ETNs including big banks series in March and April 2024, alongside redemptions of select ETNs in July 2024; additionally, in February 2025, BMO partnered with REX Shares to launch enhanced U.S. Big Banks leveraged and inverse leveraged ETNs (3X variants BNKU and BNKD) on NYSE Arca, expanding the product lineup while maintaining BNKO as the core 2X offering. Headquartered in Toronto, Canada, Bank of Montreal, through its U.S. operations, issues the full MicroSectors suite globally via NYSE Arca, with no subsidiaries directly tied to BNKO.