Oct 16 (Reuters) - Boeing ( BA ) is closing in on a plan

to raise around $15 billion with common shares and a mandatory

convertible bond as the jet maker bolsters finances worsened by

a crippling strike, four sources familiar with the matter told

Reuters.

The company on Tuesday said in regulatory filings that it

could raise as much as $25 billion in stock and debt with its

investment-grade credit rating at risk. One of the sources

cautioned that a $15 billion sale may not be enough for Boeing ( BA )

to fix its ongoing crises.

Boeing ( BA ) on Tuesday also announced a $10 billion credit

agreement with major lenders - Bank of America ( BAC ), Citibank

, Goldman Sachs ( GS ) and JPMorgan ( JPM ) - as it tries

to work out of a production and regulatory crisis.

Boeing ( BA ) was not immediately available for comment.

Four investor and banking sources said representatives from

those lenders were inquiring about appetite for a combined

offering of new shares and a mandatory convertible bond - a

hybrid bond that could convert into equity on or before a

predetermined date.

Roughly $10 billion in new shares are being contemplated to

be sold by the company along with nearly $5 billion in mandatory

convertible bonds, the sources said.

One of the four sources said the deal was scheduled to be

priced shortly after Boeing's ( BA ) Oct. 23 third-quarter earnings

report. But another investor source said the company was trying

to avoid a raise during the middle of the month-old strike which

analysts estimate is costing tens of millions of dollars per

day.