Index Ventures’ Jahanvi Sardana shares the truth about TAM and what founders should focus on instead

Early stage founders cannot stay away from TAM-the concept of a market that can be totally treated to start operating to disrupt and oppress. But Jahanvi Sardana, Index Ventures partner, has a reminder to all these founders who are concerned about finding TAM for their products or their service: Many emerging companies appeared from the markets that were at that time not mainly present.

“What is the market for search before Google?” Sardana asked the audience at the TECHRUNCH’s 2025 All Stage event in Boston, which was held earlier this month. “What is the Microsoft operating systems market, or the market for Cloud before Amazon?”

Sardana is completely compared to browsing. Every few years, there are the huge surfing founders that must be installed – first they came online, then the mobile wave, then the cloud, and now, as she said, the largest wave ever: artificial intelligence.

“Have you formed the right product to ride this wave?” It continued. “This is what we call the suitability of the product market.”

In what complete bucket are you in?

Sardana Tam puts three buckets: the well -known market, the emerging market and the invisible market.

The first known market, already exists, and when the founder seeks to replace the old workshop and must be proven to the investor why the idea of starting operation is better.

She said, “Everyone brushes their teeth.” “You have to tell me why you are building a better toothbrush.”

The emerging market is when a specific sector of the market uses a product, and there is a possibility to fall.

“Think of the non -alcoholic beer before it becomes cold,” said Sardana.

Then there is an invisible market, Sardana calls “the largest trap”, and “also a little dark art.”

The market does not exist, and the founder must mainly create one and provide investors with evidence of their innovation.

“Think of smartphones in 2006; no one knows that they want them and changed the world,” she said, adding later that “people do not know what they are looking for and sometimes you should show them what is possible.”

The audience in all theater, many of them are the founders of the early stage, are very full of questions, about what investors want to see. For example, does investors want to see the TAM chip on the stadium platform?

“There is nothing wrong with creating this slide and talking about mathematics behind completely,” Sardana said, although she added that sometimes investors feel annoyed when the founders depend a lot on industry standards instead of having their unique vision. Sardana also warned the founders not to rely heavily on industry reports. If the founder relies heavily on an external service to dictate how he thinks about the market, he can indicate that they did not think deeply in the market they are trying to build.

“How can you size TAM in the markets, especially large markets?” A member of one audience asked.

“Well, this question hurts me,” Sardana narrated. After all, pass the index once on Airbnb, after I thought Tam was very small.

“The truth is that Airbnb has created a fully new inventory, and it is now larger than some of the largest brands of hotels, which led to a major change in behavior on how people travel,” she said, adding that Tams Marketplace is difficult. “You want to focus, again, what opens the show, and as soon as the show opens, how will the behavior change?”

The audience also asked Sardana what causes the company to stand out for the investor as herself.

Sardana, which is difficult, said, but it is really important. She added that if the founder can understand who is the customer and why is ready to buy their products, the company will not face any problem in standing for investors.

“We are in the field of evaluation of the founders more than markets, products, or anything else,” she said. “When you talk about the market, it is really a lens on your ambition.”