What happened

Shares of Ocugen (OCGN -0.96%) were slipping 5% lower as of 11:27 a.m. EDT on Thursday. The company didn't announce any new developments, so what's behind this decline? One potential reason relates to Ocugen's inclusion in the Russell 3000 index.

So what

Ocugen announced a few weeks ago that its shares would be included in the Russell 3000, which tracks the performance of the 3,000 largest stocks traded in the U.S. This change took effect as of the market close on June 28.

It's probably no coincidence that the biotech stock has fallen since then. Why? Any mutual funds or exchange-traded funds that track the Russell 3000 had to buy shares of Ocugen with its inclusion in the index. Between the date Ocugen announced that it would join the index and the effective date of the addition, its shares soared more than 30%.

Doctor giving a shot to a person with another healthcare professional looking on.

Image source: Getty Images.

Now, though, most (if not all) of the funds have completed their purchases of Ocugen. The stock is returning to its normal trading without the benefit of the temporary catalyst.

Now what

The main thing to watch with Ocugen is its progress toward winning regulatory approval or authorization for COVID-19 vaccine Covaxin. Ocugen's best chances of getting the vaccine on the market in the near term could be in Canada. In early June, the company announced the expansion of its commercialization rights with Bharat Biotech, the maker of Covaxin, to include Canada in addition to the U.S.