SurveyMonkey shares fell 11 percent on Monday after one of the survey software vendor's major competitors, Qualtrics, disclosed in its IPO filing that it's the bigger of the two companies and is growing much faster than its rival.

SurveyMonkey, which trades under the name SVMK, dropped $1.39 to $11.63 at the close on Monday, its lowest price since its Nasdaq debut last month. The company has lost one-third of its value since closing at $17.24 on Sept. 26, its first trading day.

Qualtrics said in its IPO filing on Friday that revenue for the first half of 2018 jumped 41.7 percent to $184.2 million. Over that same stretch, SurveyMonkey reported 14 percent growth to $121. 2 million in sales. Qualtrics also had a narrower loss than SurveyMonkey and even turned a profit last year.

Both companies are part of a wave of subscription software developers to head for the public markets in 2018, a group that includes DocuSign, Dropbox, Zuora and Anaplan.

Also on Monday, Credit Suisse initiated coverage of SurveyMonkey with a "neutral" rating because the stock, as of the day's open, was trading within 10 percent of the firm's target price. J.P. Morgan started coverage with an "overweight" rating, citing the company's efficient business model and expectations that revenue growth will accelerate in a year.

— CNBC's Jordan Novet contributed to this report.

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