What happened

It's been tough sledding of late for billionaire Carl Icahn's namesake master limited partnership Icahn Enterprises (IEP -3.66%). Through the first three and a half days of trading this week, the diversified holding company's units shed 16% of their value, according to data provided by S&P Global Market Intelligence.

Since the start of May, Icahn Enterprises' unit price has fallen by a staggering 38%, in part in response to the publication of a short-seller report from Nathan Anderson's Hindenburg Research on May 2.   

So what

In the report, Anderson's self-styled financial forensics firm called the holding company's valuation into question, along with the sustainability of its enormous dividend, which at recent share prices yields more than 20%. On Wednesday, Icahn responded to Hindenburg's various allegations for the second time this month.

Unfortunately, his response failed to assuage investors' concerns. The key reason is that earlier that day, Icahn Enterprises posted disappointing first-quarter results. Lowlights from the report included a $270 million net loss for the period and a 36.5% year-over-year drop in revenue. 

Now what

Is it time to catch this falling knife? Probably not. While Icahn Enterprises has a long track record of delivering market-beating returns, its first-quarter performance was concerning. As such, the smarter move would likely be to wait until the company's fortunes show signs of improvement before buying units.