LightPath Technologies Inc. (LPTH) is learning a familiar Wall Street lesson: investors don't love dilution. The optical components maker saw its stock tumble in after-hours trading Thursday following news of a proposed public offering.

What's Happening

After the closing bell, LightPath announced it's launching an underwritten public offering of common stock. The company didn't disclose how many shares it plans to sell, but it's giving underwriters the standard 30-day option to purchase up to an additional 15% of whatever gets offered—what's known in finance as the greenshoe option.

So where's the money going? LightPath says it intends to deploy the net proceeds toward working capital, investments and acquisitions, plus general corporate purposes. That's fairly standard language that essentially means "keeping the lights on and pursuing growth opportunities."

Context matters here. As of September 30, LightPath had about $11.51 million in total cash and cash equivalents—not exactly a war chest for an ambitious growth company. The company also filed for a mixed shelf offering of up to $200 million back in November, giving it the flexibility to raise capital when market conditions seem favorable.

Why Shares Are Falling

Stock offerings typically pressure share prices for a straightforward reason: they dilute existing shareholders. When a company issues new shares, each existing share represents a smaller slice of the overall pie. Investors who bought yesterday suddenly own a slightly smaller percentage of the company today.

LPTH Price Action: LightPath shares were down 7.89% in after-hours trading at $8.40 at the time of publication Thursday.