Shares of MoviePass majority owner Helios and Matheson Analytics Inc. HMNY, -10.00 ballooned nearly 22% in premarket trade on Tuesday after the movie theater subscription service said its subscriber base has surpassed 600,000 members. Two months ago the company lowered the price of its subscription to $10 a month from as much as $50. Before the price cut MoviePass had roughly 20,000 subscribers. The company said that number rose to more than 150,000 just a few days after the decrease. MoviePass said the continued growth has exceeded initial expectations. The company also said that its subscriber churn rate has been shrinking, from 4.2% in the first month to 2.4% in month two. "Month after month we aim to improve our service with faster card delivery, improved application updates and an easier-to-use web site," MoviePass Chief Executive Mitch Lowe said in a statement. "I believe our ongoing investments in customer experience, usability and convenience have steadily improved customer satisfaction and retention." Shares of Helios and Matheson have gained more than 300% in the year to date, while the S&P 500 index SPX, +0.31% is up nearly 15% and the Dow Jones Industrial Average DJIA, -0.01% is up close to 18%.