Xanadu Quantum Technologies (NASDAQ: XNDU, TSX: XNDU) listed on Nasdaq and the TSX on March 27, 2026, the first pure-play photonic quantum computing company on a major exchange. Deal materials put its market capitalization near $3.6 billion at listing. Six months later, the stock trades near $7.40, down roughly 26% from its early September level, with a market cap around $2.2 billion.

That drawdown doesn’t settle the underlying question. A useful qubit can plausibly be made of light. Whether a useful machine can be built on the same 300-millimeter wafer lines that already serve silicon photonics, at a cost structure that clears, has not been shown.