Shares of ride-hailing service Lyft (LYFT) - Get Report fell more than 7% on Wednesday to $53.99 after the company revealed that its "lock-up period" will end on Aug. 19, about a month sooner than some analysts expected.

The company went public on March 29. The lock-up period, when underwriters agree not to sell their shares, typically is 180 days.

"We and the underwriters may release certain stockholders from the market standoff agreements or lock-up agreements prior to the end of the lock-up period," the company stated in a regulatory filing dated Aug. 13.

In a note on Wednesday, J.P. Morgan analyst Doug Anmuth said the expected date was Sept. 24, when about 258 million shares may become eligible for sale. That's about 75% of the current fully diluted share count, he said.

(This story has been updated: Anmuth changed his share count to 75% from 82%).

"We note that Lyft indicated that co-founders Logan Green & John Zimmer, along w/CFO Brian Roberts, who collectively own ~5-6% of shares, will not be selling at the lock-up expiration," wrote Anmuth, who has an overweight rating on Lyft's stock. "Certain shareholders deemed affiliates will also likely be subject to Rule 144 volume restrictions, including large shareholders such as Rakuten (~10%), Andreessen Horowitz (~5%), & Alphabet (~4%), all of which have Board presence."

He said about 65 million shares are subject to Rule 144 restrictions, "which limit selling in any 90 day period to the greater of 1% of shares outstanding or the average of the preceding 4 weeks trading volume, the latter of which is currently ~16.6M shares."

At the current preceding four-week average, Amuth noted that Rakuten would be most restricted given that it owns more than 31 million shares.

Lyft shares have fallen about 25% from their IPO price of $72. The stock has gained about 15% from its low of $47.17 on May 13.