144 is for restricted stock transactions when the company has released the stock from the restrictions.
"Form 144 is required when corporate insiders want to dispose of company stock. Form 144 is a notice of the intent to sell restricted stock, typically acquired by insiders or affiliates in a transaction not involving a public offering. The stock is restricted because it must meet certain conditions before becoming transferable. The transaction, or at least part of it, is made within 90 days of filing. Form 144 is required when the amount sold during any three-month period exceeds 5,000 shares or $50,000."
That's why Form 144 instead of Form 4
?