Shares of Habit Restaurants Inc have increased by more than double. On Thursday, the Habit burger chain debuted on the NASDAQ and priced its stock at $18 a share. It closed up nearly 120% at $39.54 a share.

The company raised at least $90 million through its public offering. The incident highlighted the increasing interest among investors for stocks of fast casual restaurant chains. Eatery joints like El Pollo Loco Holdings Inc and Zoe's Kitchen Inc are grabbing the attention of people by introducing new ingredients and options, like gluten-free foods.

Including Habit, five restaurant operators have raised about US$486 million in US IPOs this year when compared with US$231 million raised by two restaurants in 2013. The Habit founded in 1969 in Santa Barbara area is quite famous for its burgers in the US.

Joseph Schuster, founder of IPO research firm IPOX Schuster LLC, affirmed that a change has been witnessed in peoples' preferences, as they are now moving from fast food to speciality restaurants.

"It's a long-term structural trend and some of these specialty IPOs fit that niche very well and there is strong underpinning demand for these deals", affirmed Schuster. Zoe's Kitchen made an IPO debut in April and during that time, its shares shot up 74%.

In fact, since then its shares have doubled. Currently, Zoe's shares are trading at 351.34 times forward earnings and El Pollo is at 48.92 times forward earnings. As per experts, sales of US fast causal restaurants will most probably exceed US$50 billion by 2018.

It shall however, be noted that all fast casual operators have been able to handle the issues revolving around their public debuts. To cite an example, Potbelly Corp's stock lost 10% of its value since listing in 2013. Papa Murphy's Holdings Inc has lost 17% of its value since it made a debut in May.