ANAB · AnaptysBio

The thesis

AnaptysBio's shares are more likely to lag the S&P 500 than lead it over the next three months. Their value rests on a Delaware court ordering Jemperli rights back from GSK's Tesaro unit, and that written Chancery judgment has no set date. The company's fiscal first-quarter 2027 release, dated 12 November 2026, says post-trial argument was heard on 20 October 2026 and a judgment is expected in the fourth quarter of 2026 or the first quarter of 2027.

The royalty business is profitable but slowing from the milestone-boosted year-ago quarter. The release reported collaboration revenue of $30.3 million for the quarter ended 30 September 2026, against $76.3 million a year earlier, when a $50 million milestone was booked. Net income from continuing operations was $3.9 million, or $0.13 per basic share, against $56.3 million a year earlier. Cash, equivalents and investments fell to $153.0 million from $164.1 million at 30 June 2026, and the release mentions no share repurchases.

The shares closed at $47.77 on 12 November 2026, 34.8% below the 52-week intraday high of $73.30 set on 13 April 2026. The shares are down 18.3% over three months on adjusted daily closes. That price already reflects a contested ruling and a royalty stream that is growing more slowly. The rating is Low because the one event that would reprice the shares has no scheduled date.

Bullish and bearish views on AnaptysBio, Inc.

The bull case on AnaptysBio, Inc. (ANAB), in brief: the court has already ruled for Anaptys once. The bear case: the legal outcome is binary and undated.

Bull case

• The court has already ruled for Anaptys once. On 24 April 2026 Delaware Chancery dismissed Tesaro's anticipatory breach claim and rejected its royalty reduction request, so current royalty rates still apply. Anaptys has said that a finding of breach on even one contract provision would return the Jemperli licence to it alone.
• Jemperli sales are still growing. The company's 12 November 2026 release reported GSK's Jemperli net sales of $365 million for the September quarter, up 20% from a year earlier, and $1.0 billion for the first nine months of GSK's year, up 29%. The royalty is tiered from 8% to 25% of net sales.
• Royalties rose from the previous quarter. The release reported Jemperli royalties up 11% from the June quarter, lifting collaboration revenue to $30.3 million from $27.5 million.
• A new Jemperli indication was approved. GSK announced on 19 October 2026 that the FDA granted accelerated approval for stage II or III MSI-H/dMMR locally advanced rectal cancer, based on the single-arm AZUR-1 trial of 154 patients.
• A second royalty has a decision date. The release gives the FDA action date for imsidolimab (licensed to Vanda) in generalised pustular psoriasis as 12 December 2026.

Bear case

• The legal outcome is binary and undated. The court has set no judgment date. GSK said on 24 April 2026 that the dismissal did not address the merits of the main contract dispute.
• Jemperli growth is decelerating. The 20% sales growth for the September quarter compares with 29% for the first nine months of GSK's year, both from the company's 12 November 2026 release.
• Cash is falling and buybacks are unused. Cash and investments were $153.0 million at 30 September 2026, down $11.1 million in the quarter from $164.1 million, with $15.5 million used in operating activities. The release mentions no repurchases under the $100 million authorisation that expires on 31 December 2026.
• Royalty cash is committed to Sagard. The release says Sagard had accrued about $330 million through 30 September 2026, and the remaining non-recourse obligation of about $270 million is expected to be paid down in the second half of calendar 2027.
• The rectal cancer label is narrow. The approval covers MSI-H or dMMR tumours only and rests on single-arm evidence (FDA and GSK, 19 October 2026).
• A director sold near the current price. SEC Form 4 filings show director Hollings Renton exercised 5,000 options at $18.03 and sold 5,000 shares at $49.87 on 1 October 2026 under a Rule 10b5-1 plan.

Price setup

The shares closed at $47.77 on 12 November 2026, below the 50-day moving average of $50.01 and the 200-day moving average of $51.12 (adjusted closes). The lowest recent close was $45.58 on 5 November 2026. The shares rose to $48.77 by 11 November 2026 and gave back $1.00 on 12 November 2026.

The 3-month reference close was $58.47 on 14 August 2026, the start of the 18.3% decline. The 52-week intraday high is $73.30 (13 April 2026). The 52-week closing low is $33.09 (12 November 2025). Both moving averages sit above the last close, and a close above them would be the first sign of the shares recovering their pre-August level.

Catalysts ahead

• 12 December 2026: FDA action date for imsidolimab (licensed to Vanda) in generalised pustular psoriasis. An approval would start a second royalty stream for AnaptysBio; a complete response letter would remove it.
• 31 December 2026: Expiry of the $100 million share repurchase authorisation. Shows whether the company uses the authorisation while the shares trade about a third below their 52-week high and cash is falling.
• ~31 December 2026 (est.): Delaware Chancery written judgment in Anaptys v. Tesaro/GSK, expected in the fourth quarter of 2026 or the first quarter of 2027; the court has set no date. The judgment decides whether Jemperli rights revert to AnaptysBio, the event that sets the shares' value.

What would change the view

A daily close above $59.69, the highest close of the 63 sessions to 17 August 2026, would show the shares leading the S&P 500 and prove this call wrong. So would a Chancery judgment ordering Jemperli rights back to AnaptysBio.

What it trades with

The shares move mainly on the Chancery docket and on GSK's Jemperli sales, which set the royalty. Vanda's imsidolimab decision on 12 December 2026 is a separate, smaller driver. The clinical pipeline went to First Tracks Biotherapeutics in the April 2026 spin-off, so the shares trade on royalty and litigation value and carry little exposure to clinical trial news. GSK's quarterly reports set the royalty data, which leaves the shares sensitive to GSK's oncology results even though they move little with GSK's broader share price.