The more Zscaler (ZS -0.16%) falls, the more shares I've been buying. I've already added to my position three times this year. With the stock recently dropping another 10% after reporting its fiscal first quarter results, -- pushing it 60% below its 52-week high -- I'm planning to add to my position again. 

Here's why I'm buying shares of this cybersecurity stock hand-over-fist this year.  

Another strong showing

Zscaler's stock shed another 10% even though it posted excellent fiscal first-quarter numbers. Revenue surged 54% to $355.5 million, while adjusted net income more than doubled from $0.14 to $0.29 per share. Both metrics surpassed analysts' expectations. 

Meanwhile, the company continues to generate free cash flow. It converted 27% of its revenue in the period into free cash. That enabled Zscaler to grow its cash by more than $90 million to $1.8 billion. That gives it a net cash position, given that its only debt is $1.1 billion of convertible senior notes. 

The company continues to benefit from strong demand for its cloud-based security platform. With cyber threats growing, more companies are switching from traditional network security setups to Zscaler's Zero Trust architecture.

Lots of growth still ahead

Despite all those positives, the growing macroeconomic uncertainty continues to weigh on Zscaler's shares. That's due to concerns its growth could slow. The company is starting to see some headwinds as customers take longer to make purchase decisions.

However, it has a strong customer retention rate in the mid-90% range. Further, it continues to successfully upsell to existing customers, evidenced by a high dollar-based net retention rate that has been above 125% for eight straight quarters. Meanwhile, even though it's taking longer to close deals, the company is seeing increasingly larger sales as customers consolidate security products by joining Zscaler's integrated security platform. 

The company believes it's in the early stages of capturing a massive total addressable market for cloud security. CEO Jay Chaudhry stated on the quarterly conference call:

Hybrid work and public cloud adoption are now mainstream as organizations. Large and small, are racing to ensure their business operations are agile, resilient, and secure. These generational tailwinds are durable and my conviction in our $72 billion serviceable market opportunity is greater than it has ever been. 

He noted that in his talks with IT executives, cybersecurity remains their No.1 priority. Attackers continue to find ways to exploit traditional firewalls and VPNs. "This is driving more organizations from firewall and VPN-based castle-and-moat security to Zscaler's Zero Trust architecture," according to comments by Chaudhry on the call. The company remains confident it can continue growing and eventually reach its next milestone of $5 billion in annual recurring revenue (ARR). Earlier this year, it achieved its target of $1 billion in ARR.

Zscaler continues investing in innovation to enhance its product portfolio and drive growth. Chaudhry highlighted the continued innovation of its data protection offering on the call, which is "gaining traction as customers are concerned about data leakage with employees working from anywhere." The company's founder also noted that "beyond our core products, we are excited about the rapid adoption of our two emerging product pillars: ZDX to manage digital user experience and Zscaler for Workloads to secure servers and workloads." Those emerging products give the company even more upselling potential, adding to the "6x upsell opportunity with our existing customers just for our core ZIA and ZPA product pillars," Chaudhry emphasized on the call. 

A massive growth opportunity

Zscaler is still only in the early innings of a significant opportunity for cloud security. The market, however, seems more focused on the current macro uncertainty than this long-term growth potential. That's why I plan to continue capitalizing on the sell-off in Zscaler and buy more shares as the stock keeps falling.