Cash, cash, and more cash.

Asa Mathat | D: All Things Digital

Relative to its auto-industry "peers," Tesla has a pitiful amount of available cash. The carmakers that Tesla has challenged in market capitalization in 2017 — General Motors, Ford, and Fiat Chrysler Automobiles — have each amassed war chests. FCA has almost $20 billion, GM has nearly $25 billion, and Ford has socked away close to $40 billion.

Tesla has just over $3 billion

Tesla is also currently burning through over a billion per quarter. If we just go by cash and exclude other financing instruments, such as Tesla's revolving credit lines, the company can't make it through 2018.

It's worth noting that Tesla is running thin on cash at a time when the US economy is at full employment and the US auto market is running near an all-time sales high.

Do the math: Tesla needs more money. And it will likely obtain that funding through another capital raise. It's past two raises were a return to Wall Street to sell more stock; and a first foray into the junk-bond debt markets.

The smart money, such as it is, would likely bet on Tesla doing another equity raise in 2018, given that shares are still above $300. Each new raise, however, highlights Tesla's poor execution on the manufacturing front. FCA, Ford, and GM also spend a billion per quarter, but they manage to produce millions of vehicles worldwide. Tesla produces a fraction of that.

There is an assumption among Tesla bulls that this pattern will at some point reverse in the future, as the Model 3 sedan, priced to start at $35,000, ramps toward full production and Tesla starts to draw in revenue from something like 400,000 pre-orders.

But while that would be cause for celebration at Tesla, attention would then turn to how much money Tesla is making on the Model 3. Mass-market sedans have notoriously skinny profit margins and have plummeted in popularity as consumers have turned to crossover SUVs.

There's no question that cash will be Tesla's biggest challenge in 2018.