What happened Shares of Appian (NASDAQ: APPN) soared on Monday. There was no company-specific news driving the rally, but the broader stock market enjoyed a strong day. Appian stock was up about 11.8% at 3:30 p.m. EST today. So what Shares of Appian had been trending downward ever since early September of last year. A secondary offering of common stock sent shares lower, and somewhat weak guidance in October didn't help the situation. The software-as-a-service company said it expected fourth-quarter revenue between $69.1 million and $70.1 million, compared with the average analyst estimate of $70.1 million. Non-GAAP (adjusted) EPS is expected to be a loss of $0.14 or $0.15, worse than the $0.11 loss analysts were expecting. Image source: Getty Images. Now what The volatility being experienced by Appian stock may have something to do with the valuation. After Monday's surge, the company is valued at about $3.3 billion, putting the price-to-sales ratio over 20, based on Appian's guidance. Revenue is expected to grow by 33% to 34% this year, which is quite a bit slower than other high-profile software-as-a-service stocks. A big rally is always exciting for shareholders, but Appian stock remains down nearly 20% since peaking late last year. Find out why Appian is one of the 10 best stocks to buy now Motley Fool co-founders Tom and David Gardner have spent more than a decade beating the market. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* Tom and David just revealed their ten top stock picks for investors to buy right now. Appian is on the list -- but there are nine others you may be overlooking. Click here to get access to the full list! *Stock Advisor returns as of December 1, 2019 Timothy Green has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Appian. The Motley Fool has a disclosure policy.Source