One of last year's biggest IPO duds is cleaning up nicely in 2018. Shares of Funko (NASDAQ:FNKO) keep climbing, hitting fresh new highs this week. The company behind the Pop! line of vinyl big-headed collectible dolls has bounced back after a rough Wall Street debut on the strength of back-to-back blowout quarters, game-changing licensing deals, and perpetually boosted guidance. 

Funko is one of this year's biggest winners, up a whopping 367% through Monday's close. It's a surprising turnaround for a company that hit the market as a broken IPO late last year. Nobody wanted a piece of Funko when it was hoping to hit the market between $14 and $16 a share in early November. Underwriters had to settle for $12, and even that was too ambitious. The stock opened at $8, and by the end of the year had whittled all the way down to $6.65. Funko seemed to be out for the count, but it was really just setting up the starting line for the mother of all rallies in 2018.

Funko illuminated sign with Funko dolls on shelves.

Image source: Funko.

Pop star

Funko is picking up the pace this year. Net sales have risen 35% through the first half of this year, up from last year's 21% clip. Growth is steady across product categories and geographical territories, something that wasn't the case late last year when domestic sales had slowed to a single-digit clip. 

There's refreshing balance these days. International sales rose 32% in Funko's second quarter, in line with the 33% domestic uptick. Sales of Funko's flagship figures rose 31% -- accounting for 83% of total sales -- with a 42% surge in other product categories. Margins are improving, and adjusted earnings more than doubled. The 121% surge was a lot better than analysts expected, just as Funko's bottom line blasted through Wall Street targets in the first quarter.  

Sentiment has clearly turned in favor of Funko this year. The Fortnite and Pokemon figures that it showed off during Comic-Con in San Diego this summer ahead of its second-half release were the toast of the iconic event.

Not everyone is sold on Funko's momentum continuing at this point. BMO Capital Markets analyst Gerrick Johnson feels that the core Pop! vinyl collectibles are closer to the end of their popularity cycle than the beginning, and his $10.50 price target on the shares is a little more than a third of where the stock is now. 

Funko's stock has likely outpaced its improving fundamentals in 2018, but it also began the year at depressed price levels. Funko keeps boosting its forecasts higher. Last month it moved the goalposts again. It is now targeting $620 million to $630 million in net sales, a roughly 15% increase. EBITDA should grow even faster, up 20% at its new midpoint. These revised metrics aren't perfect, suggesting decelerating growth as the balance of 2018 plays out. A broadening arsenal of products gives it a better chance of landing products that resonate with fans of its licensed franchises, but it also wouldn't be a surprise to see the stock take a breather from being one of this year's biggest upside surprises.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.