NEW YORK ( TheStreet) -- The frenzy and scrutiny surrounding Apple ( AAPL) highlights the challenging psychology of owning the iPhone maker's stock, according to investor Vitaliy Katsenelson, chief investment officer of Investment Management Associates. Apple shares have fallen 13% this year and are down double that amount over six months, as investors have started to question the company's growth potential. Once seemingly unstoppable, Apple saw its fourth-quarter earnings miss consensus estimates and the company took another hit last month when its first-quarter revenue failed to meet Wall Street's expectations. Institutional Investor Web site, however, Katsenelson says that understanding Apple requires an analysis of fundamentals and psychology. "What makes Apple stock difficult to own is psychology," he wrote, comparing the company's success since 2000 to a "black swan" phenomenon. "We tend to think of Nassim Nicholas Taleb's black swans as significant random negative events, but Apple is a positive one." Katsenelson notes that Apple co-founder Steve Jobs pulled off a "miracle" when he returned to the company in the late 1990s, making Macs exciting and unleashing the revolutionary iPod, iPhone and iPad. "You could argue that the success of each 'I' product in itself was a black swan, exceeding all rational expectations and revolutionizing, transforming and in some cases creating new categories of merchandise that had never existed before," he said. The CIO, who recently bought Apple shares for clients at $450, nonetheless acknowledges the uniqueness of investing in the tech giant. warned that, at the moment, there's little Apple can do or say outside of a new product that will assuage investors' fears over slowing growth. Apple shares gained 0.2% to reach $458.88 during Wednesday trading. -- Written by James Rogers in New York Follow @jamesjrogers >To submit a news tip, send an email to: email@example.com.