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Stock lending and short volume tracker

The Lending page of GEXStream shows, for more than 600 tickers, the daily stock loan balance reported by the OCC (Options Clearing Corporation), the daily short volume published by FINRA (the Financial Industry Regulatory Authority), and days to cover (DTC) derived from FINRA's twice-monthly short interest, each with a z-score that says how unusual today's reading is against that ticker's own history. It is the one page on the site about the stock itself rather than its options chain.

GEXStream Lending page: the Market Aggregate chart with loan balance and short volume lines and their dotted z-score lines, a loan and short percent change chart below, and a table of 640 tickers with loan, short volume and z-score columns beside a pinned $MARKET row.
The Market Aggregate view over three months: loan balance (gold) and short volume (blue) with their z-score lines dotted, the percent change chart below, and the table with the $MARKET row pinned above 640 tickers. The Days to Cover column was added after this capture.

What it shows

Three feeds, joined by ticker in one table and two stacked charts.

Four z-score columns sit beside the raw values: LZc and SZc score today's percent change, LZv and SZv score today's level, and the DTC cell is coloured by its own z-score against that ticker's recent settlements. A $MARKET row pinned at the top aggregates the S&P 500 constituents only, with no exchange-traded funds (ETFs) or indices, so hedging-driven ETF lending does not blur the equity reading. The tracked list holds 655 symbols across the S&P 500, major ETFs and additional widely traded names.

How to read it

Loan balance is a stock measure (capital currently deployed in borrows) and short volume is a flow measure (what happened today). Both rising reads as fresh shorts being opened; short volume up with the balance flat reads as intraday churn; short volume up with the balance falling reads as covering. The formulas and the full reading list are in the lending section of the docs.

Days to cover adds a position level that neither daily column carries: how crowded the short is relative to normal trading. Its level is not a direction on its own; the direction of its change is what carries information. On the tracked universe the median sits near 3 days.

Colour is the first pass: a z-score beyond 2 in either direction is red (extreme), beyond 1 is orange (stretched), and inside 1 is gray (normal). Sorting a z-score column sorts by magnitude, so the most unusual names in both directions rise together.

How the z-scores are computed

Every z-score in the table is measured against a 12-month window of that ticker's own history, with the value being scored excluded from its own population. A ticker needs at least three days of history before the table shows a z-score for it.

Short interest is only knowable once FINRA publishes it, about nine business days after the settlement date, and the page respects that: each chart row shows the settlement published as of that date, never one that had settled but was not yet public.

Table and charts

The table lists every tracked ticker with data on both of the latest two days, in 10 sortable columns ordered by loan balance by default. The search field takes up to 10 comma-separated tickers and the My list chip narrows the table to your watchlist. Clicking a row loads that ticker into the charts; $MARKET is the default selection.

The upper chart plots loan balance in dollars against short volume in shares on separate axes, with the loan z-score, the short z-score and days to cover as extra series from the legend; days to cover draws as a step line, flat between settlements, with gaps where nothing had been published. The lower chart overlays loan and short percent change. Range buttons cover all data, 3 months, 2 months and 1 month, and a distribution strip at the right edge sketches where each visible series has spent its time.

Update cadence

The server checks the OCC file and the FINRA short volume feed every two hours and the short interest feed every 12 hours; results are cached for five minutes, and an open page re-requests the table every hour. In practice loan balances arrive once per weekday, short volume one session later, and days to cover twice a month.

Which plans include it

The lending tracker is included on the Flow and Quant plans, and every part of this page needs Flow: the table, the charts, the z-scores, days to cover and the $MARKET aggregate. Quant adds nothing here; Basic does not include the page. See plans and pricing.

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