Apple dipped below $400 for the first time since April as a glut of unsold iPhones prompted Jefferies & Co. to lower its target price, and Global Equities Research said low morale is causing employee departures.

Apple, the world’s most valuable technology company, fell 2.7 percent to $402.54 at the close in New York yesterday, after earlier dropping as low as $398.05. The shares have declined 24 percent this year, compared with a 10 percent gain in the Standard & Poor’s 500 Index.

The stock has retreated 43 percent from a record high in September amid concern that CEO Tim Cook has taken too long to deliver a new breakthrough product to help make up for stiffer iPhone competition.

Retailers and wireless carriers have twice the normal levels of iPhone inventory, indicating that Apple is selling fewer handsets than expected, said Peter Misek, an analyst at Jefferies.

Trip Chowdhry, an analyst at Global Equities, also said morale is low and more Apple workers are seeking jobs at companies such as Google and Facebook.