Citigroup’s (NYSE: C) cyber security budget jumped to $300 million at the end of last year while Wells Fargo (NYSE: WFC) spends roughly $250 million a year on cybersecurity and has increased staffing in the area by 50%, according to the Wall Street Journal.

Increased cyber security spending by financial services firms is seen as a boon for companies such as FireEye (NasdaqGS: FEYE), Palo Alto Networks (NasdaqGS: PANW) and Japan’s Trend Micro. All three are members of HACK’s portfolio with FIreEye and Palo Alto Networks combining for 9.7% of the ETF’s weight.

Earlier this week, HACK surged after Russia’s Kaspersky Lab, a major cyber security firm, said a group of hackers have stolen as much as $1 billion from over 100 banks in 30 countries since late 2013.

Investors are buying into the thesis that increased cyber security spending bodes well for HACK’s longer-term potential. The ETF that the fund is now home to $231 million in assets under management, confirming HACK’s place on the list of most successful ETFs to debut in 2014. Impressively, HACK’s ascent to $231 million in AUM means the ETF has more than doubled in size over the past six weeks after topping $100 million in assets in early January. The ETF debuted in November. [Cyber Security ETF Tops $100M in AUM]

PureFunds ISE Cyber Security ETF