NEW YORK (AP) — Lululemon Athletica’s CEO Christine Day may not be a household name to the athletic wear company’s legions of loyal shoppers. But for investors, she’s the face of the chain.

Lululemon’s shares plunged 17 percent and several Wall Street analysts downgraded their ratings on the stock on Tuesday, a day after the company announced that Day, 51, planned to step down. Under Day’s leadership over the past five years, Lululemon has achieved meteoric growth by attracting yogis and others willing to shell out $100 for yoga pants.