Mr Cosby was one of a half-a-dozen investors rumoured to have approached GE in the past year with offers to buy the troubled network, only to have balked at the dollars 3bn-dollars 4bn price the conglomerate is seeking.
GE, which acquired the network in 1986 as part of its dollars 6.4bn (pounds 4.2bn) acquisition of the RCA electronics group, has since said it is not interested in selling NBC. But analysts on Wall Street believe that Mr Cosby's attempt to line up a bid is 'real' and that GE would sell at the right price.
While it carries the network on its books at a value of dollars 3.8bn, GE 'would probably accept an offer it can present as a legitimate valuation for the network', said Lisbeth Barron, media analyst with SG Warburg in New York. 'There are not going to be that many buyers out there for NBC.'
NBC, the top-ranked US broadcaster when GE bought it in the 1980s, has since slipped to third place in viewer ratings and its annual profits have declined to dollars 50m a year from about dollars 600m as audiences have been fragmented among dozens of new cable TV channels.
But some investors see new value in the traditional TV networks, thanks in part to recent regulatory changes that have allowed them to share in the profits of re-runs of programmes.
The Wall Street investment firm Goldman Sachs is advising Mr Cosby, who began his TV career in the NBC series I Spy in the mid-1960s and whose Cosby Show ranked as the network's most popular for years.
Some analysts believe that Mr Cosby, whose personal fortune is put at dollars 300m, might team up with other investors who earlier expressed interest in the network, notably Paramount Communications, the parent of the Hollywood studio.
Paramount would not comment on Mr Cosby's plans. Public relations staff at NBC were not returning reporters' telephone calls yesterday afternoon.
Mr Cosby has made no secret of his interest in reviving NBC's fortunes, showing up unexpectedly at a recent meeting of local TV stations that are affiliated to the network.
Mr Cosby reportedly gave a five-minute speech praising recent changes in NBC's management, concluding with a promise 'to see this peacock fly again', a reference to the network's multi-coloured logo.
One option some analysts believe is being considered by GE is an offer to break NBC into two companies, one broadcasting national news and sports programmes, the other using the network to air entertainment programming supplied by one or more Hollywood production studios.