A tiny biotech company focused on breast cancer treatments has soared 29% amid Reddit hype

• Atossa Therapeutics rallied 29% Tuesday on hype from retail traders on Reddit.
• Redditors cheered that the company will soon be included on the Russell 2000 and 3000 indexes.
• The Seattle-based biopharmaceutical is focused on developing its breast-cancer treatment.

Shares of a tiny biopharmaceutical company soared 29% Tuesday as Reddit retail traders boosted the stock.

Atossa Therapeutics, the Seattle-based biopharmaceutical focused on developing a breast-cancer treatment, was one of the top-trending stocks on popular Reddit investing threads Tuesday, according to HypeEquity data. The shares have gone on a nearly two-week rally that's brought the company's market capitalization close to $1 billion.

On Reddit's penny stocks forum, one post with 1,400 upvotes, a.k.a likes, read, "ATOS is still on track to rocket. While some of the gains have been achieved already, the major gains are yet to come."

The company announced last week it would be added to the Russell 2000 and Russell 3000 indexes on June 28, which the Reddit post said would trigger "massive share buying." The Redditor, who has 23,000 "post karma," also noted the company's short-squeeze potential.

"I really don't know why in 2021 funds are taking these huge short positions anymore, but ATOS is a stock with heavy short interest," said the Redditor, who did not immediately respond to Insider's request for comment.

Since the short squeeze in GameStop's stock earlier this year, Redditors have become known for driving short sellers to cover their bearish bets. And Atossa has a 19% short-volume ratio, according to data from Fintel.io.

Another catalyst for retail-trader hype came earlier this month when Atossa announced it received approval from Swedish regulators to initiate its phase 2 study of Oral Endoxifen. The drug aims to reduce mammographic breast density, which reduces the ability of mammograms to detect breast cancer and increases the risk of developing it. The company did not immediately respond to Insider's request for comment for the story.