RPG Options Traders Buy While Short Sellers Pile In

Why this matters: Three distinct lending and positioning signals converged on RPG — the Invesco S&P 500 Pure Growth ETF — within a single session. Short positions have more than doubled in a month. Yet options traders are the most bullish they've been in three weeks. The divergence is sharp.

Short Sellers Build Fast

Short interest in RPG has risen 55.6% in one week. Over the past month, it has doubled — up 106%. Estimated shares short now stand at around 359,000. That puts short interest at approximately 1.1% of free float. Absolute levels are low, but the pace of accumulation is the story. From mid-August's lows, shorts have added steadily and accelerated sharply since September 11.

Borrow Costs Rise as Availability Tightens

The cost to borrow RPG has climbed 76% in one week, reaching 1.62%. A month ago it sat near 1.14%. Borrow availability has tightened considerably. Availability stood above 800% on September 4. By September 17, it had dropped to roughly 210% — a fall of nearly 50% in one week. That still represents a normal lending environment with ample supply, but the directional shift is notable. The 52-week minimum availability recorded was 11.4%, suggesting the pool can tighten far further if demand continues.

The ORTEX short score has climbed from 30.7 on September 4 to 41.2 on September 17. It is not yet at an extreme level, but the trajectory is consistent and uninterrupted.

Options Market Reads It Differently

The put-call ratio tells a different story. RPG's PCR hit 0.0172 on September 17 — the lowest reading in 20 days. The 20-day average sits at 0.0206. The z-score of −2.0 places this reading two standard deviations below the recent mean. Call volume is dominant. Options traders are leaning bullish on the growth factor, even as the borrow market signals increasing hedging demand.

This divergence — shorts building, borrowing getting more expensive and scarcer, but calls overwhelming puts — reflects a genuine split in near-term positioning across participant types.

Data Summary

• Short Interest % of Float: 1.06%, up 55.6% in one week, up 106% in one month
• Cost to Borrow: 1.62%, up 76% week-on-week
• Borrow Availability: ~210%, down ~49% in one week (52-week low: 11.4%)
• Put-Call Ratio: 0.0172, z-score −2.0 vs. 20-day mean of 0.0206
• ORTEX Short Score: 41.2 (rising from 30.7 two weeks ago)
• Price: $56.40, up 1.3% on the day but down 7.4% over the past month

What to watch: Whether borrow availability continues tightening toward the 52-week lows, and whether the options positioning shifts to close the gap with short-side activity.