Volume and Interest

In the five trading days ended Oct 17, 49.1% of average daily stock volume was short.

“Wait, what?” you say.  “Half the stock market is short?”

Yes, that’s right.  Short volume last topped 49% marketwide in mid-April. The market glided gently downward from there to May options-expirations. Speaking of expirations, we’re in them for October this week, so it’s a good time to talk about shorting.

Short volume hit a last marketwide low July 12 at 43%, which roughly corresponded to the high point of the Brexit Bounce.  At Nov 30 last year short volume was 42.9% and December and January were horrific for markets.  And on Jan 7, 2016, short volume was 52%. A month later the market bottomed and soared till April.

If short-volume history is a guide, the market is nearing a temporary bottom. It’s unwise to use a single data point, and we don’t (we use six key measures, plus a small supporting cast, as you clients know). The flow and behavior of money count, and we track both.

“Back up,” you say.  “You lost me at ‘short volume.’ What do you mean by that?”

Short volume is trading derived from borrowed shares.

“I read back in August on Zero Hedge that nobody’s short stocks. Trading from borrowed shares is 2% of the S&P 500, near a three-year low.”

You’re talking about short interest, the long-in-the-tooth risk-assessment tool derived from a 1975 Federal Reserve rule called Regulation T. Shorting and derivatives exploded after the US scrapped the gold standard and the Feds wanted to track margin accounts.

“Are we talking about the same short interest? The amount of total shares outstanding or float that’s borrowed and sold and not yet covered?”

Yes. Forty-one years later it’s still a standard market-risk measure. Yet it’s largely useless predictively. It didn’t shoot up until well after Bear Stearns foundered. In late 2007 it was 1.6%.

“So you’re saying it’s a crappy measure. What’s short volume then?”

Short volume is the amount of daily trading volume that’s borrowed. If a stock trades a million shares a day and short volume is 53%, then 530,000 shares of it were borrowed.  With over 40% of all market volume coming from Fast Traders wanting to own nothing, a great deal of this is short-term trading.

“Okay, I’m following. But what’s it tell me?”

Short volume signals several things but in sum it’s what you think: High short volume, lower price.  Why? Shorting is at root the continual adding of supply to the market. So if demand doesn’t keep up, price falls.

Here’s more:

High short volume means weak expectation for gains. No matter what company fundamentals are, if more volume comes from borrowed shares than owned shares, Fast Traders weighing tick data with high performance machines predict investors would rather lend shares for a return than spend money buying and holding them.

High short volume points to rotation. If the machines want to be short, they’re betting holders are selling and trying to hide it by passing shares through multiple brokers. The converse is true too: If you’ve been short and shorting falls, rotation is probably done.

Persistent high shorting reflects uncertainty about corporate strategy.  Not to pick on Tesla (because it’s not alone by any stretch) but its 200-day average short volume is 55%. Investors say it’s a trading vehicle, not an investment opportunity.  By contrast Qualcomm’s 200-day average is 42%. The two have inverse performance the past year.

Tangentially, high short volume CAN mean ETFs are seeing outflows. Exchange Traded Funds don’t directly buy or sell stocks but they create big volume because ETFs track other measures, such as indexes, that are in turn composed of other issues, such as stocks.

Traders measure deviation between ETFs and these other things and arbitrage (profit on price-differences) the spreads.  When investors sell ETF shares, ETF market makers or authorized participants (parties designated to create and redeem ETF shares) might short components to raise cash in order to buy ETF shares and retire them to rebalance supply.

In sum, short volume is a sensor situated near the beating heart of the money behind price and volume. And while algorithms driving trades today are designed to deceive, they can often be unmasked through short volume (with a couple other key measures).

For the rest of this week though, don’t be surprised if the market shows us not a beating heart but expirations-related palpitations.