GIGAMON LLC (GIMO) IPO

We estimate that the net proceeds to us from the sale of shares of our common
stock in this offering will be $       million, based on an assumed initial
public offering price of $       per share, which is the midpoint of the
estimated offering price range set forth on the cover page of this prospectus,
after deducting estimated underwriting discounts and commissions and estimated
offering expenses payable by us. If the underwriters’ option to purchase
additional shares from us is exercised in full, we estimate that our net
proceeds would be $       million, after deducting estimated underwriting
discounts and commissions and estimated offering expenses payable by us. We will
not receive any proceeds from the sale of shares of our common stock by the
selling stockholders.

Each $1.00 increase or decrease in the assumed initial public offering price of
$       per share would increase or decrease the net proceeds that we receive
from this offering by $       million, assuming that the number of shares
offered by us, as set forth on the cover page of this prospectus, remains the
same, after deducting estimated underwriting discounts and commissions payable
by us. Similarly, each increase or decrease of one million in the number of
shares of common stock offered by us would increase or decrease the net proceeds
that we receive from this offering by $       million, assuming the assumed
initial public offering price remains the same and after deducting estimated
underwriting discounts and commissions payable by us.

The principal purposes of this offering are to increase our financial
flexibility, to create a public market for our common stock and to facilitate
our future access to the public equity markets.

We currently intend to use the net proceeds that we will receive from this
offering to satisfy our obligations to holders of performance units under our
2009 Performance Unit Plan, who are primarily our employees, which we estimate
will be $       in cash in the aggregate, based on an assumed initial public
offering price of $       per share, which is the midpoint of the estimated
offering price range set forth on the cover page of this prospectus. Each $1.00
increase or decrease in the assumed initial public offering price would increase
or decrease, as applicable, the cash payments by us to holders of performance
units by $      . Payments pursuant to our 2009 Performance Unit Plan will be
recorded as compensation charges.

We currently intend to use the balance of the net proceeds that we will receive
from this offering for working capital and other general corporate purposes. We
may also use a portion of the net proceeds that we receive to acquire or invest
in complementary businesses, products, services, technologies or other assets.
We have not entered into any agreements or commitments with respect to any
acquisitions or investments at this time.

We cannot specify with certainty all of the particular uses of the net proceeds
that we will receive from this offering. Accordingly, we will have broad
discretion in using these proceeds. Furthermore, the amount and timing of our
actual expenditures will depend on numerous factors, including the cash used in
or generated by our operations, the status of our development, the level of our
sales and marketing activities and our investments and acquisitions. Pending the
use of proceeds from this offering as described above, we plan to invest the net
proceeds that we receive in this offering in short-term and intermediate-term
interest-bearing obligations, investment-grade investments, certificates of
deposit or direct or guaranteed obligations of the U.S. government. We cannot
predict whether the invested proceeds will yield a favorable return.

The markets in which we compete are highly competitive. We expect competition 
to intensify in the future as existing competitors bundle new and more 
competitive offerings with their existing products and services, and as new 
market entrants introduce new products into our markets. 

We compete either directly or indirectly with Ethernet switch vendors, such as 
Cisco Systems, Inc., Juniper Networks, Inc., Brocade Communications Systems, 
Inc. and Arista Networks, Inc., and network management, analysis, compliance 
and security tool vendors that offer point solutions that address a portion of 
the issues that we solve. In the future, we expect to compete with new market 
entrants, which may include our joint-development partners or other current 
technology partners. 

The principal competitive factors applicable to our products include: 

. functionality and performance; 

. price and total cost of ownership; 

. ease of use; 

. flexibility and scalability of deployment; 

. brand awareness; 

. product reliability and quality; 

. interoperability with other products; 

. the extent and speed of user adoption; and 

. quality of service, support and fulfillment. 

Although we believe that we compete favorably with respect to the above factors,
we believe that other competitors will emerge that may have greater name 
recognition, longer operating histories, well-established relationships with 
end-user customers or channel partners in our markets, broader product 
portfolios and the ability to bundle competitive offerings with other products 
and services, larger intellectual property portfolios and substantially greater
financial, technical, personnel and other resources than we have. We expect 
competition and competitive pressure, from both new and existing competitors, 
to increase in the future.