Here's an excerpt from the Charles Schwab website which I think will help evaluate your position:
The simple answer to your question is no, the value of a gift of stock
for gift tax liability is NOT the donor's cost basis, but rather the
fair market value of the stock at the time the gift is given. So let's
say you purchased 100 shares of XYZ stock at $50 a share. Your cost
basis is $5,000. Now the stock is $80 a share and you give it as a
gift. The value of your gift for gift tax purposes is $8,000.
In 2015, you can give up to $14,000 to an unlimited number of
individuals each year without paying a gift tax or even reporting the
gifts. If you give over that amount to any individual, however, you
must report the gift on your tax return, but you don't have to pay
taxes until you give away more than the current lifetime limit of
$5,430,000—for the amount above and beyond $14,000 per person per
year. So in the example above, there would be no gift tax liability.
However, if the stock happened to be $150 a share, the value of the
gift would be $15,000. You'd then have to report it and $1,000 would
be applied toward your $5,430,000 lifetime exclusion.
You will need to pay a gift tax on the current value of the stock. I'm not familiar with the tax laws in India, but if your brother was in the US, he wouldn't pay taxes on that gift until he sells the stock.
The recipient doesn’t have to worry about gift taxes. It's when the
recipient decides to sell the stock that the issue of valuation comes
up—for income taxes. And this is where things can get a bit more
In general, when valuing a gift of stock for capital gains tax
liability, it's the donor's cost basis and holding period that rules.
As an example, let's say you receive a gift of stock from your
grandfather. He bought it for $10 a share and it's worth $15 a share
on the day you receive it. If you then sell the stock, whether for a
gain or a loss, your cost basis will be the same as your
grandfather’s: $10 per share. Sell it at $25 and you'll pay tax (at
the short- or long-term rate, depending on how long he owned the
stock) on a gain of $15 a share; sell it at $8 and your capital loss
will be $2 a share.
Ultimately, with a gift this large that also crosses international borders, you really should hire a professional who is experienced with these types of transactions. Their fees/commission will be completely offset by the savings in risk and paperwork.