As we wrote almost a year to the day in the pages of all our editions - French and international - CoStar has indeed long been a caricatural example of a serial acquirer whose buy-and-build strategy destroys value on a large scale.

Over the past decade, the group led by Andy Florance has directed $4.4bn into a string of secondary portal acquisitions whose audience remains incomparably smaller than the market leaders - for example Zillow in the US, Rightmove in the UK, or REA in Australia.

While the group's revenue has indeed more than quadrupled over the period, from $840m to $3.2bn, operating profit before investment - or EBITDA - has been flat, even as the number of shares outstanding rose by a quarter.

Last year, the group also began building a new mega-campus in Richmond, Virginia - a huge project that includes a 26-story tower and a six-story building, with a cost that could range between $460m and $500m.

This may have been the straw that broke the donkey's back for many shareholders, no longer able to turn a blind eye to operating cash flow that has stagnated - and even declined - since 2019, while capex has, in the meantime, literally increased tenfold.

CoStar must quickly offer reassurances and prove its ability to get its accounts back into the black. If one goes by the analyst consensus surveyed in real time by MarketScreener, the beginning of an inflection is precisely expected this year. It is not certain that this will be enough to justify a valuation above 8x  revenue.

It is striking that the UK-based Rightmove, admittedly extraordinarily profitable, turned down a $9bn takeover bid - equivalent to a third of CoStar's enterprise value - even though its revenue is six times smaller.

https://www.marketscreener.com/news/costar-in-the-crosshairs-of-famed-activist-dan-loeb-ce7e5bdddf81f62d