Weekly Check-In: TSM, BRK.B, AMZN, SPY

TSM jumped to $428.18 on September 4, up about 2.7% from the prior close of $417.01 and outperforming the S&P by roughly 2.5 percentage points -- a company-specific move rather than broad risk-on sentiment. Stifel initiated coverage with a Buy on September 1, joining an already bullish analyst base (average 12-month target $552.38, high estimate $700). Management struck an optimistic tone on silicon photonics capturing over half its addressable market next year, co-packaged optics production starting before year-end, and a potential new AI-infrastructure growth wave in 2028; a $1.114 dividend was also declared, ex-date September 16. The standing overhang hasn't gone anywhere: Taiwan is reportedly weighing stricter export controls (with potential criminal penalties) on advanced AI chips to China, and existing US controls already cap TSM's ability to expand its Nanjing fab, ceding ground to SMIC and Hua Hong -- a reminder that TSM alone still produces roughly 90% of the world's advanced semiconductors, making the China-Taiwan relationship the single largest tail risk sitting underneath this position.

AMZN sits at $258.90, essentially flat on the week after dipping to $259.77 on September 1 when the FTC and 22 state attorneys general sued Amazon in Seattle federal court, alleging it secretly inflated sponsored-ad auction prices for advertisers over more than seven years -- regulators claim over $20B in overcharges to 1.2M+ advertisers since 2019, including an allegation that Amazon used an "invented auction participant" to push prices higher. Amazon denies wrongdoing and says average winning bids actually fell 50% since 2019, but the suit seeks civil penalties and restitution, so there's real financial exposure beyond the headline. This landed against a strong fundamental backdrop: Q2 revenue of $200.6B (+20% YoY) and EPS of $5.75 beat estimates, and AWS grew 36.7% YoY to $42.2B, its fastest growth in 18 quarters. Analyst sentiment remains Strong Buy (59 buys, 0 sells), average target $328.17.

BRK.B trades at $508.13, up modestly from $505.24, still comfortably inside its 52-week range ($464.01-$537.74) with the next earnings report not due until November 2. The concentration trend this journal has been tracking has only deepened: Greg Abel now has 63% of Berkshire's roughly $355-360B equity portfolio parked in just five stocks -- Apple, American Express, and Alphabet among the largest -- after jettisoning 16 positions and trimming six others in Q1, leaving the top 10 holdings at about 90.7% of total assets. That's a continuation, not a reversal, of the pivot toward tech and away from decades-old positions this journal first flagged with the Alphabet buying in August; the risk is straightforward -- a portfolio this concentrated means a sharp move in any one of the five names now has an outsized effect on Berkshire's reported results.

SPY closed Thursday at $773.17, up 1.05% on the day from Wednesday's $765.16, putting the index right back near its 52-week (and all-time) high of $779.37. No single catalyst drove the move; broad market strength across the board. Worth flagging plainly for the journal: sitting this close to record highs isn't a valuation-conscious entry point, whatever the near-term momentum looks like.

This week's pattern: TSM and the broad index both pushed higher on company- and market-specific strength, while AMZN absorbed a real legal risk without denting the underlying growth story, and Berkshire kept leaning further into concentration under Abel. None of the four names' core narratives changed direction this week -- the moves were incremental, and the risks (Taiwan/China for TSM, the FTC suit for AMZN, concentration for BRK.B, and valuation for the index itself) are all ones already on this journal's radar rather than new surprises.