Early-stage founders just can’t receive away from TAM — the concept of having a total addressable market for their startup to disrupt and conquer. But Index Ventures partner Jahanvi Sardana has a reminder for all those founders worried about finding TAM for their product or service: Many startups have emerged from markets that, at the time, were essentially nonexistent.
“What was the market for search before Google?” Sardana inquireed the audience at TechCrunch’s 2025 All Stage event in Boston, held earlier this month. “What was the market for operating systems before Microsoft, or the market for cloud before Amazon?”
Sardana compares TAM to surfing. Every few years, there are massive waves founders must ride — first came the internet, then the mobile wave, then the cloud, and now, she stated, the hugegest wave of all: artificial innotifyigence.
“Have you shaped the right product to ride this wave?” she continued. “That’s what we call product-market fit.”
Which TAM bucket are you in?
Sardana places TAM into three buckets: known market, emerging market, and invisible market.
The first, known market, already exists, and it is when a founder seeks to replace a legacy incumbent and must prove to an investor why their startup idea is better.
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“Everyone brushes their teeth,” she stated. “You have to notify me why you’re building a better toothbrush.”
The emerging market is when a certain sector of the market is utilizing a product, and there is potential for it to go mainstream.
“Think about non-alcoholic beer before it became cool,” Sardana stated.
Then there is the invisible market, which Sardana calls “the hugegest trap,” and “also a little bit of a dark art.”
The market doesn’t exist, and a founder has to essentially create one and provide investors with evidence of how innovative they can be.
“Think about smartphones in 2006; nobody knew they wanted them and they alterd the world,” she stated, later adding that “people don’t know what they’re seeing for and sometimes you have to display them what’s possible.”
The audience at All Stage, many of whom are early-stage founders, peppered Sardana with questions, largely about what investors want to see. For instance, do investors want to see a TAM slide in a pitch deck?
“It’s OK to create that slide and talk about the math behind your TAM,” Sardana stated, though she added that sometimes investors receive annoyed when founders rely too much on indusattempt metrics rather than having their own unique insight. Sardana also cautioned founders not to rely too much on indusattempt reports. If a founder is too depfinishent on an external service to dictate how they believe about the market, it can signal that they haven’t believed deeply about the market they are attempting to build in, she commented.
“How do you size the TAM in the marketplaces, especially huge marketplaces?” one audience member inquireed.
“Well, that question hurts,” Sardana quipped. After all, Index once passed on Airbnb, having believed its TAM was too compact.
“The reality is Airbnb created a whole new inventory, which is now hugeger than some of the largest hotel brands, and that led to a huge alter in behavior on how people travel,” she stated, adding that marketplace TAMs are tricky. “You want to focus on, again, what is unlocking supply, and once you unlock the supply, how will behavior alter?”
The audience also inquireed Sardana what creates a company stand out to an investor like herself.
A tough one, Sardana stated, but a really important one. Ultimately, if a founder can understand who the customer is and why they are willing to purchase their product, then a company should have no problem standing up to investors, she added.
“We’re in the business of evaluating founders more than markets or products or anything else,” she stated. “When you talk about your market, it’s really a lens on your ambition.”
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