Unless the polls are systematically biased or there is a late-breaking surge in support for “Yes,” the “No” campaign looks set to squeak by with a narrow victory in the Scottish independence referendum. On the betting markets, a “Yes” vote has plunged below an implied probability of 20%. What has this decline in the prospects for independence done to capital markets? In my last post on the subject, I found that British firms and the pound were nearly untouched by what was at the time significant momentum for “Yes,” but that a nine-firm Scottish equity index was hit hard. If those losses reflected unease about independence, then the latest news should have caused growth in my Scottish equity index.
The biggest decline in the Yes team’s chances actually came overnight September 11-12, when the chances of Scottish independence abruptly fell about 10 percentage points on the release of new polls in the evening of September 11. (For a full list of recent polls, see Wikipedia.) The Yougov poll showing “No” in the lead (a dramatic reversal from its previous poll) seems to have been leaked just before the closing bell on September 11.
Accordingly, I examine the performance of the Scottish equity index on the London Stock Exchange between 4:30 PM and 5:00 PM local time on September 11, when the odds of Scottish independence declined so rapidly. These are the nine stocks I include in the index: SL, SSE, FGP, WEIR, SGC, AGGK, WG, ADN, and MNZS. Of these, eight of nine rose on the poll news. Again, I weight by each stock by its market cap to create the index. The index rose 0.5% on the news, a rather small increase compared to the 1.7% decline after the shock Yougov poll showing “Yes” ahead. The overall patterns were pretty similar, though. The two transportation companies, Firstgroup and Stagecoach Group, were basically unchanged between the two. Energy-linked firms and Standard Life led gainers. Aggreko (temperature control systems) registered a small gain, and Aberdeen Asset Management a somewhat larger one.
Roughly a ten-percentage-point drop in independence likelihood led to a 0.5% gain in the value of Scottish equities, less than a third of the loss in Scottish equities after an eight-percentage-point gain in independence likelihood just a few days prior. On balance, these results suggest we should revise downward the costs of secession suggested by the prior post.
One objection to this interpretation might be that the leak of the Yougov poll just before the closing bell gave traders little time to respond. But this does not appear to be the case. The Scottish equity index was flat at the opening bell on September 12, suggesting that there was no new information for traders to consider.
Here are two more interpretations. First, betting markets are less liquid and well-capitalized than financial markets. The actual gain in the probability of Scottish independence after the first Yougov poll may have been greater than the immediate response on betting markets. Second, the shock of a poll actually showing “Yes” ahead may have led traders to overestimate the likelihood of Scottish independence, and perhaps even the costs of secession (in a moment of panic). Having been inured to the initial shock and its aftermath, traders then took later news with more equanimity.
Overall, though, the results are still suggesting net economic costs to Scottish independence. How much of the emphasis should be put on the “Scottish” part of that phrase and how much on “independence” remains a matter of debate, but clearly energy and financial firms are more affected than transportation and service ones.