Tech spending doesn't have to collapse for tech stocks to lose leadership. Jim Paulsen compares technology-related spending with its long-run trend. His concern is the speed of the recent expansion: "It's just too extreme, too much, too fast." "Even if it stays fairly strong, if it just is less strong, I think that's gonna have an impact on leadership."

An AI chip can still work and already be uneconomic. "It's not that the chip broke and stopped working. It's uneconomic relative to buying more of these." Rob Arnott draws on Chris Brightman's research: what if newer chips make old ones uneconomic after three years, while the purchase is depreciated over six? "I'm not saying the AI revolution isn't real. It's very real."

"We're never gonna run out of data to process." Ed Yardeni sees data as a new factor of production alongside land, labor and capital. Cheaper processing, he argues, creates more demand for computing. "The question is: how do you make money on that?" His approach is to own the Nasdaq-100: "Some companies in there are really gonna make a lot of money" and "the other ones will just go away."

"I think it largely gets the direction right, but the magnitude wrong." Expensive companies can grow faster and still fail to justify their prices. With earnings expectations helping push stocks to record highs, Cliff Asness's research asks the relevant question: did growth over the next three or five years match what investors paid for?

Governments and the AI buildout are competing for the same pool of money. "They all are enormous sponges for capital." Ben Hunt on the crowding out effect that AI borrowing creates.

A passive portfolio can hide an active bet. "You're really actively choosing to bet the farm on one thing." Jason Hsu worries that investors buying the S&P 500 for diversification may underestimate their exposure to the same AI growth story.

Demanding revenue too early can damage the business you invested in. Jack Raines noticed that some pre-revenue investments in his seed-stage fund performed better than businesses already making sales. Pushing for a top-line number too soon "might actually kill the ability for the rocket growth later."

If SpaceX joins the S&P 500, index funds could rush to buy from holders who do not want to sell. "Like a herd of elephants trying to get through a revolving door at the same time." Rob Arnott argues that funds trying to match the index's closing price can crowd into the same trade. Minimizing tracking error does not necessarily mean getting a good purchase price.

"All too often, people assume that something as complex as financial markets requires a complex solution, and it really doesn't." "The key to success is just minimizing mistakes and not interrupting compounding." Peter Lazaroff on the one lesson he would teach the average investor.

Tom Maher on when basket trades overpower company fundamentals. "People hate company B, and this is in a basket with company B, so it's getting dragged down." These moves can persist for "six, nine, 12 months, not one or two days."

Last week's AI selloff puts an old investing problem back in focus: a technology can change the world without rewarding the people funding it. Ben Inker's earlier warning: "You get way too much investment and you destroy that ROI." "It doesn't mean that the technology doesn't change the world."

Better or worse may matter more than good or bad. Jim Paulsen on why changes in expectations matter more to asset prices than whether the economy looks strong in isolation.

"The surefire winners of the internet boom were Yahoo, AOL, and Cisco." Chris Davis sees a warning in treating today's AI leaders as inevitable winners.

A crisis can make changes possible that a struggling business has resisted for years. "The biggest home run for us was Rolls-Royce, the engine manufacturer." Colin McQueen backed its pandemic fundraising with a restructuring thesis: the crisis could help management tackle restrictive labor practices and divisions lagging their peers. He later roughly quadrupled his estimate of the company's cash-generation potential.

A resilient S&P 500 can hide the pressure higher rates are putting on the companies inside it. "It's because they're pressuring underneath the surface." Paisley Nardini is still optimistic about the market. But smaller and midsize companies that need outside financing, have less free cash flow or face heavy capital spending are feeling the squeeze.

"The incentives in the industry, on average, are not in the favor of the customer." "Look for the incentives of the people selling to you." Gary Mishuris on the one lesson he would teach the average investor.

"By the 15th iteration, it is awesome." Barry Ritholtz on why the first AI answer is a starting point, not the finished product.

You do not have to be first to an investing idea. Being too late can be the bigger problem. When "your cousin who's got nothing to do with finance calls you up asking about it," it might be time to move on. Tian Yang on narratives as an S-curve.