SmileDirectClub, the direct-to-consumer aligner company, recorded the fifth worst IPO debut this year, according to CNBC, with the company’s shares plummeting 28% on its first day of trading.

The company’s shares opened at $20.55 and ended the day at $16.67.

For its market debut on Thursday, September 12, SmileDirectClub priced its initial public offering at $23 per share, above the expected range of $19 to $22.

According to Yahoo Finance, for an IPO selling $500 million in shares or more, this is the worst first-day performance since at least 2000.

On its second day of trading, the stock closed at $18.68—up 12% over the previous day.

The company filed to go public in August.