Shares of Opendoor Technologies Inc (OPEN) tumbled 5.04% in pre-market trading on Wednesday, following a late Tuesday announcement by notorious investor Martin Shkreli, also known as 'Pharma Bro', that he has taken a short position against the iBuying real estate company.

Shkreli revealed on social media platform X that he shorted OPEN stock at $9.36, marking his first trade in the company. The controversial figure also declared his intention to launch a public due diligence campaign into the firm, stating, "I will be doing diligence calls with former employees, customers, competitors, and hopefully, management too!" This move signals Shkreli's intent to not only bet against the company but also to publicly build a bearish case against it.

The bearish pressure on Opendoor isn't limited to Shkreli alone. Famed short-seller Andrew Left of Citron Research recently called the company "a science project in how to burn money." This increased scrutiny comes after OPEN's stock experienced a meteoric rise from its 52-week lows, gaining over 1,000% at one point and attracting the "meme stock" label. The stock has advanced 461.01% year-to-date, despite the recent pullback. As the battle between retail bulls and institutional bears intensifies, investors will be closely watching the impact of Shkreli's public short position and investigation on OPEN's stock performance in the coming days.