Europe trades cheap because its firms cannot scale, and that does not mean revert

Back out the levels the column implies, and the arithmetic hangs together. A $3 trillion gap that represents about a third more than Europe's total puts Europe near $9 trillion in 2008 and the US near $12 trillion ^[1]. Quadruple the first and add 70% to the second and you arrive at roughly $48 trillion against roughly $15 trillion, a gap of about $33 trillion, within rounding of the $34 trillion reported ^[2]. The ratio went from about 1.3 to about 3.1 in fifteen years ^[2]. Annualised, that is 9.7% a year for US listed equity against 3.6% for Europe ^[4]. Six points a year, compounded, is what a binding constraint looks like when it shows up in a price series.

The GDP-scaled version is the one worth pinning to a wall. Europe's listed market was 63% of GDP in 2023 ^[4], which is fifteen points below where the US already stood in 2008 ^[5]. Europe in 2023 had not reached the US starting line of the period under study.

The mechanism the authors propose is that European firms stay tethered to their home market and that small ones face a much larger cost of capital with no way to swap debt for equity, venture capital included ^[8][9]. The supporting literature they cite is consistent: internal barriers inside the single market estimated at two to three times those between US states, according to Cerdeiro and Rotunno ^[10], and European venture investment at a fraction of the American level, according to Lerner ^[11]. Note where that leaves the youth diagnosis. Adilbish et al. tie Europe's productivity weakness to a shortage of dynamic young firms and a surplus of mature, small, underperforming ones ^[14]. A surplus of old small firms is not an age problem. It is evidence that firms which survive still do not grow, which is the same finding the valuation decomposition reaches from the market side, where the gap sits in the value of the average firm rather than in the count of firms or the sector mix ^[7].

For an allocator, the awkward part is the loop. A high cost of equity for small European firms is, by definition, a low price on those firms ^[9]. Buy the discount and you are buying the input to the weak growth that produced the discount. Nothing in that arrangement unwinds on sentiment or on a cheaper euro. It unwinds if cross-border frictions fall or if European savings get intermediated into equity rather than sitting elsewhere, which is Garnier's framing of the problem ^[12]. That is legislative plumbing on a multi-year clock, not a quarter-end catalyst, and the Draghi Report already put the financing of young, fast-growing firms at the centre of its diagnosis in 2024 ^[13].

Two cautions on the evidence. This is one VoxEU column by three finance academics summarising their own new paper, using aggregate market data and firm-level balance sheets from 2008 to 2023 ^[16]. Ruling out superstar concentration ^[5], New York listings by European-headquartered firms ^[6], firm counts and sector composition ^[7] is a decomposition, not a proof of causation, and the cost-of-capital channel is asserted more than it is demonstrated in the space of a column. It does, however, point the same direction as Reichardt and Reis, who attribute the productivity gap to the higher efficiency of the US financial market ^[15]. What the ledger cannot tell you is how much of the $34 trillion ^[2] the plumbing would actually recover.